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Bytecodealliance

47 CVEs vendor

Monthly

CVE-2026-54786 Jul 01, 20:12 Cargo LOW PATCH GHSA Monitor

Resource exhaustion in Wasmtime's native WASIp1 implementation allows low-privileged WebAssembly guests to exhaust host-level file descriptors and OS resources by repeatedly invoking fd_renumber in a loop. The affected versions span four distinct release branches - all pre-24.0.10, 25.x-35.x, 37.x-44.x, and 45.0.0-45.0.1 - but only runtimes that both expose fd_renumber and grant guests the ability to open files are vulnerable. No public exploit code exists and the issue is not listed in CISA KEV; however, the attack is mechanically straightforward once the conditions are met, making patching the primary defense.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub
CVSS 4.0
2.3
EPSS
0.2%
CVE-2026-35195 Apr 09, 18:55 Cargo MEDIUM PATCH GHSA This Month

Wasmtime prior to versions 24.0.7, 36.0.7, 42.0.2, and 43.0.1 allows authenticated remote attackers to corrupt memory by providing malicious realloc return values during string transcoding between WebAssembly components, enabling writes to arbitrary memory locations up to 4GiB away from linear memory base. On default configurations with 4GiB virtual memory reservation and guard pages, exploitation typically triggers process abort via unmapped memory access; however, configurations with reduced memory reservation and disabled guard pages risk corruption of host data structures or other guest linear memories.

Buffer Overflow Memory Corruption Red Hat Wasmtime Suse +1
NVD GitHub VulDB
CVSS 4.0
6.1
EPSS
0.0%
CVE-2026-35186 Apr 09, 18:54 Cargo MEDIUM PATCH GHSA This Month

Wasmtime versions 25.0.0 through 36.0.6, 42.0.0-42.0.1, and 43.0.0 contain a compiler type-checking bug in the Winch backend where the table.grow operator returns incorrectly typed 64-bit values instead of 32-bit values for 32-bit tables, enabling read/write access to 16 bytes of host memory preceding linear memory and resulting in denial of service when Wasmtime detects the unauthorized access. The vulnerability requires explicit selection of the non-default Winch compiler backend and either disabled guard pages or modified memory layout to achieve information disclosure; default Wasmtime configurations using the Cranelift compiler and standard guard page placement are unaffected. No public exploit code or active exploitation has been identified, though the attack vector is remote and requires low-privilege authenticated access.

Denial Of Service Red Hat Wasmtime Suse Bytecodealliance
NVD GitHub VulDB
CVSS 4.0
6.1
EPSS
0.0%
CVE-2026-34988 Apr 09, 18:52 Cargo LOW PATCH GHSA Monitor

Wasmtime's pooling allocator leaks linear memory contents between WebAssembly instances when configured with specific non-default settings (memory_guard_size=0, memory_reservation<4GiB, max_memory_size=memory_reservation). Affected versions 28.0.0 through 36.0.6, 42.0.0-42.0.1, and 43.0.0 allow authenticated local attackers with high attack complexity to read sensitive data from previously-mapped memory due to incorrect virtual memory permission reset logic. Vendor-released patches: 36.0.7, 42.0.2, and 43.0.1. No public exploit identified at time of analysis.

Buffer Overflow Wasmtime Bytecodealliance
NVD GitHub VulDB
CVSS 4.0
2.3
EPSS
0.0%
CVE-2026-34987 Apr 09, 18:48 Cargo CRITICAL PATCH GHSA Act Now

Memory sandbox escape in Wasmtime's Winch compiler (versions 25.0.0 to before 36.0.7, 42.0.2, 43.0.1) enables authenticated WebAssembly guests to access arbitrary host process memory outside linear-memory boundaries. Exploitation requires non-default Winch backend activation via -Ccompiler=winch flag. Attackers can read up to 32KiB before memory start or ~4GiB after, with theoretical potential for unlimited in-process memory access due to improper 32-bit offset handling in 64-bit registers. Consequences include host process crashes (DoS), sensitive data exfiltration, or remote code execution through memory writes. Affects aarch64 (confirmed PoC) and x86-64 (theoretical). Publicly available exploit code exists.

Buffer Overflow Information Disclosure Red Hat Wasmtime Suse +1
NVD GitHub VulDB
CVSS 4.0
9.0
EPSS
0.0%
CVE-2026-34983 Apr 09, 18:47 LIB LOW PATCH GHSA Monitor

Wasmtime 43.0.0 contains a use-after-free vulnerability in the Linker cloning mechanism that allows host embedders to trigger memory corruption through a specific sequence of API calls: cloning a wasmtime::Linker, dropping the original instance, and then using the cloned instance. This vulnerability is not exploitable by guest WebAssembly programs and requires deliberate misuse of the host API. The flaw is fixed in Wasmtime 43.0.1. Despite the use-after-free nature (CWE-416), the CVSS 4.0 score of 1.0 reflects the extremely limited attack surface: physical or local access is required (AV:P), attack complexity is high (AC:H), high privilege level is needed (PR:H), and user interaction is required (UI:A), resulting in minimal confidentiality, integrity, and availability impact.

Information Disclosure Use After Free Memory Corruption Wasmtime Bytecodealliance
NVD GitHub VulDB
CVSS 4.0
1.0
EPSS
0.0%
CVE-2026-34971 Apr 09, 18:45 Cargo CRITICAL PATCH GHSA Act Now

Arbitrary memory read/write vulnerability in Bytecode Alliance Wasmtime versions 32.0.0 through 36.0.6, 42.0.0-42.0.1, and 43.0.0 allows authenticated remote attackers to escape WebAssembly sandbox restrictions. The Cranelift compilation backend on aarch64 architecture miscompiles specific heap access patterns, creating divergent address computations where bounds checks validate one address while loads access another, enabling sandbox escape through unrestricted host memory access. Exploitation requires 64-bit WebAssembly linear memories with Spectre mitigations and signals-based-traps disabled. No public exploit identified at time of analysis.

Buffer Overflow Information Disclosure Wasmtime Bytecodealliance
NVD GitHub VulDB
CVSS 4.0
9.0
EPSS
0.0%
CVE-2026-34946 Apr 09, 18:43 Cargo MEDIUM PATCH GHSA This Month

Wasmtime's Winch compiler (versions 25.0.0 through 36.0.6, 42.0.0-42.0.1, and 43.0.0) contains a table indexing vulnerability in the table.fill instruction that causes host panic when compiled by Winch on any architecture. A valid WebAssembly guest can trigger this denial-of-service condition due to incorrect table reference indexing left behind after a historical refactoring. EPSS score of 5.9 reflects medium exploitability, and the vulnerability is patched in Wasmtime 36.0.7, 42.0.2, and 43.0.1.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub VulDB
CVSS 4.0
5.9
EPSS
0.0%
CVE-2026-34945 Apr 09, 18:40 Cargo LOW PATCH GHSA Monitor

Wasmtime's Winch compiler in versions 25.0.0 through 36.0.6, 42.0.1, and 43.0.0 incorrectly translates the WebAssembly table.size instruction for 64-bit tables under the memory64 proposal, allowing WebAssembly guests to read sensitive data from the host's stack. The vulnerability stems from static typing the return value as 32-bit instead of consulting the table's actual index type, which when combined with Winch's multi-value return ABI mechanics enables stack data disclosure. This is fixed in Wasmtime 36.0.7, 42.0.2, and 43.0.1; no public exploit code or active exploitation has been identified at time of analysis, but the low CVSS score (2.3) reflects limited real-world impact due to authentication requirements and limited technical scope.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub VulDB
CVSS 4.0
2.3
EPSS
0.0%
CVE-2026-34944 Apr 09, 18:38 Cargo MEDIUM PATCH GHSA This Month

Wasmtime's Cranelift compiler generates inefficient code for the f64x2.splat WebAssembly instruction on x86-64 platforms with SSE3 disabled, causing it to load 8 excess bytes beyond the intended operand. On systems with signals-based traps disabled, this overflow access can trigger segmentation faults from unmapped guard pages; with guard pages also disabled, out-of-sandbox memory is accessible to the runtime (though not to WebAssembly guests themselves). The vulnerability affects Wasmtime versions prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, and is fixed in those releases. No public exploit code or active exploitation (KEV) is documented.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub VulDB
CVSS 4.0
4.1
EPSS
0.0%
CVE-2026-34943 Apr 09, 18:36 Cargo MEDIUM PATCH GHSA This Month

Wasmtime runtime before versions 24.0.7, 36.0.7, 42.0.2, and 43.0.1 panics when lifting component model flags-typed values with out-of-specification bit patterns, enabling guest-controlled denial-of-service in the host environment. The vulnerability requires high privilege and user interaction but affects a critical WebAssembly runtime used in production systems. No public exploit code is confirmed at time of analysis.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub VulDB
CVSS 4.0
5.6
EPSS
0.0%
CVE-2026-34942 Apr 09, 18:32 Cargo MEDIUM PATCH GHSA This Month

Wasmtime prior to versions 24.0.7, 36.0.7, 42.0.2, and 43.0.1 fails to properly validate pointer alignment when transcoding strings into UTF-16 or Latin-1+UTF-16 encodings within the Component Model, allowing authenticated malicious WebAssembly guests to trigger host panics by passing specially crafted unaligned pointers across component boundaries. This denial-of-service vulnerability requires authenticated access and specific string configurations but results in controllable host crashes. CVSS score 5.9 reflects moderate severity with attack vector network and authentication requirement; SSVC framework rates exploitation as not yet observed with non-automatable exploitation.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub VulDB
CVSS 4.0
5.9
EPSS
0.0%
CVE-2026-34941 Apr 09, 18:29 Cargo MEDIUM PATCH GHSA This Month

Wasmtime runtime versions prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1 incorrectly validate UTF-16 string byte lengths during component-model encoding transcoding, causing out-of-bounds memory reads that trigger process termination via segfault in default configurations or potentially expose host memory when guard pages are disabled. Authenticated users with UI interaction can trigger this denial-of-service vulnerability; reading beyond linear memory requires non-standard Wasmtime configuration without guard pages. No public exploit code has been identified at time of analysis.

Buffer Overflow Information Disclosure Wasmtime Bytecodealliance
NVD GitHub VulDB
CVSS 4.0
6.9
EPSS
0.0%
CVE-2026-27572 Feb 24, 22:16 Cargo HIGH PATCH This Week

Wasmtime's HTTP header handling in the wasmtime-wasi-http crate crashes when processing excessive header fields, allowing remote attackers to trigger denial of service against applications embedding Wasmtime. The vulnerability affects versions prior to 24.0.6, 36.0.6, 40.0.4, 41.0.4, and 42.0.0, and has been patched to return a controlled trap instead of panicking. Embedders should update immediately to mitigate this DoS vector.

Denial Of Service Industrial Red Hat Wasmtime Bytecodealliance
NVD GitHub
CVSS 3.1
7.5
EPSS
0.1%
CVE-2026-27204 Feb 24, 22:16 Cargo MEDIUM PATCH This Month

Uncontrolled resource allocation in Wasmtime's WASI host interfaces allows authenticated guests to trigger denial of service on the host system by exhausting resources without proper limits. Affected versions prior to 24.0.6, 36.0.6, 40.0.4, 41.0.4, and 42.0.0 require explicit configuration to mitigate this issue, though Wasmtime 42.0.0 and later provide secure defaults. No patch is currently available for older versions, and resource exhaustion protections must be manually enabled.

Denial Of Service Red Hat Wasmtime Bytecodealliance
NVD GitHub
CVSS 3.1
6.5
EPSS
0.1%
CVE-2026-27195 Feb 24, 22:16 Cargo HIGH PATCH This Week

Wasmtime versions 39.0.0 and later experience a denial-of-service panic when async WebAssembly component functions are called and then abandoned by the host before completion, such as when the Future is dropped after a single poll during an async yield. This affects applications using Wasmtime's component model with async support, allowing an attacker to crash the runtime through specially crafted async function invocations. A patch is available to address this stability issue.

Golang Industrial Red Hat Wasmtime Bytecodealliance
NVD GitHub
CVSS 3.1
7.5
EPSS
0.1%
CVE-2026-24116 Jan 27, 19:16 Cargo MEDIUM PATCH This Month

Wasmtime versions 29.0.0 through 41.0.0 on x86-64 platforms with AVX contain an out-of-bounds memory read in the f64.copysign instruction compilation that can cause application crashes when signal-based traps are disabled. In configurations with disabled guard pages, this vulnerability could potentially leak out-of-sandbox data, though the data remains inaccessible to WebAssembly guests without additional Cranelift bugs. Patches are available in versions 36.0.5, 40.0.3, and 41.0.1.

Buffer Overflow Information Disclosure Wasmtime Bytecodealliance
NVD GitHub
CVSS 3.1
5.5
EPSS
0.0%
CVE-2025-64713 Nov 25, 23:15 MEDIUM POC This Month

WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (Wasm) runtime. Rated medium severity (CVSS 5.1), this vulnerability is no authentication required. Public exploit code available and no vendor patch available.

Buffer Overflow Webassembly Micro Runtime Bytecodealliance
NVD GitHub
CVSS 3.1
5.1
EPSS
0.0%
CVE-2025-64704 Nov 25, 23:15 MEDIUM POC This Month

WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (Wasm) runtime. Rated medium severity (CVSS 4.7), this vulnerability is no authentication required. Public exploit code available and no vendor patch available.

Information Disclosure Webassembly Micro Runtime Bytecodealliance
NVD GitHub
CVSS 3.1
4.7
EPSS
0.0%
CVE-2025-58749 Sep 16, 16:15 LOW POC PATCH Monitor

WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (Wasm) runtime. Rated low severity (CVSS 2.1), this vulnerability is no authentication required, low attack complexity. Public exploit code available.

Denial Of Service Integer Overflow Webassembly Micro Runtime Bytecodealliance
NVD GitHub
CVSS 4.0
2.1
EPSS
0.1%
CVE-2025-43853 May 15, 18:15 HIGH POC PATCH This Month

The WebAssembly Micro Runtime's (WAMR) iwasm package is the executable binary built with WAMR VMcore which supports WebAssembly System Interface (WASI) and command line interface. Rated high severity (CVSS 7.0), this vulnerability is no authentication required, low attack complexity. Public exploit code available.

Windows Information Disclosure Microsoft Webassembly Micro Runtime Bytecodealliance
NVD GitHub
CVSS 4.0
7.0
EPSS
0.1%
CVE-2024-27532 Nov 08, 22:15 HIGH POC This Week

wasm-micro-runtime (aka WebAssembly Micro Runtime or WAMR) 06df58f is vulnerable to NULL Pointer Dereference in function `block_type_get_result_types. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Denial Of Service Null Pointer Dereference Webassembly Micro Runtime Bytecodealliance
NVD GitHub
CVSS 3.1
7.5
EPSS
0.5%
CVE-2024-25431 Nov 08, 17:15 HIGH POC PATCH This Week

An issue in bytecodealliance wasm-micro-runtime before v.b3f728c and fixed in commit 06df58f allows a remote attacker to escalate privileges via a crafted file to the check_was_abi_compatibility. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. Public exploit code available.

Buffer Overflow Information Disclosure Webassembly Micro Runtime Bytecodealliance
NVD GitHub
CVSS 3.1
7.8
EPSS
0.6%
CVE-2024-51745 Nov 05, 22:15 Cargo LOW PATCH Monitor

Wasmtime is a fast and secure runtime for WebAssembly. Rated low severity (CVSS 2.3), this vulnerability is remotely exploitable, low attack complexity.

Authentication Bypass Microsoft Wasmtime Bytecodealliance
NVD GitHub
CVSS 4.0
2.3
EPSS
0.8%
CVE-2024-47813 Oct 09, 18:15 LIB LOW PATCH Monitor

Wasmtime is an open source runtime for WebAssembly. Rated low severity (CVSS 2.9). No vendor patch available.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub
CVSS 3.1
2.9
EPSS
0.2%
CVE-2024-47763 Oct 09, 18:15 LIB MEDIUM PATCH This Month

Wasmtime is an open source runtime for WebAssembly. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity.

Denial Of Service Google Wasmtime Bytecodealliance
NVD GitHub
CVSS 3.1
5.5
EPSS
0.2%
CVE-2024-34251 May 06, 16:15 HIGH POC This Week

An out-of-bound memory read vulnerability was discovered in Bytecode Alliance wasm-micro-runtime v2.0.0 which allows a remote attacker to cause a denial of service via the "block_type_get_arity". Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Buffer Overflow Denial Of Service Information Disclosure Webassembly Micro Runtime Bytecodealliance
NVD GitHub
CVSS 3.1
7.5
EPSS
0.8%
CVE-2024-34250 May 06, 16:15 MEDIUM POC This Month

A heap buffer overflow vulnerability was discovered in Bytecode Alliance wasm-micro-runtime v2.0.0 which allows a remote attacker to cause at least a denial of service via the "wasm_loader_check_br". Rated medium severity (CVSS 6.2), this vulnerability is no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Buffer Overflow Denial Of Service Heap Overflow Webassembly Micro Runtime Bytecodealliance
NVD GitHub
CVSS 3.1
6.2
EPSS
0.3%
CVE-2024-30266 Apr 04, 16:15 LIB MEDIUM POC PATCH This Month

wasmtime is a runtime for WebAssembly. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. Public exploit code available.

Information Disclosure Memory Corruption Wasmtime Bytecodealliance
NVD GitHub
CVSS 3.1
5.5
EPSS
0.3%
CVE-2023-52284 Dec 31, 06:15 MEDIUM POC PATCH This Month

Bytecode Alliance wasm-micro-runtime (aka WebAssembly Micro Runtime or WAMR) before 1.3.0 can have an "double free or corruption" error for a valid WebAssembly module because. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, low attack complexity. Public exploit code available.

Information Disclosure Webassembly Micro Runtime Bytecodealliance
NVD GitHub
CVSS 3.1
5.5
EPSS
0.3%
CVE-2023-48105 Nov 22, 23:15 HIGH POC PATCH This Week

An heap overflow vulnerability was discovered in Bytecode alliance wasm-micro-runtime v.1.2.3 allows a remote attacker to cause a denial of service via the wasm_loader_prepare_bytecode function in. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

Buffer Overflow Denial Of Service Memory Corruption Webassembly Micro Runtime Bytecodealliance
NVD GitHub VulDB
CVSS 3.1
7.5
EPSS
1.3%
CVE-2023-41880 Sep 15, 20:15 Cargo MEDIUM PATCH This Month

Wasmtime is a standalone runtime for WebAssembly. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub
CVSS 3.1
5.3
EPSS
0.6%
CVE-2023-30624 Apr 27, 17:15 Cargo HIGH PATCH This Week

Wasmtime is a standalone runtime for WebAssembly. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub
CVSS 3.1
8.8
EPSS
0.4%
CVE-2023-27477 Mar 08, 21:15 Cargo MEDIUM PATCH This Month

wasmtime is a fast and secure runtime for WebAssembly. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity.

Information Disclosure Wasmtime Cranelift Codegen Bytecodealliance
NVD GitHub
CVSS 3.1
4.3
EPSS
0.6%
CVE-2023-26489 Mar 08, 20:15 Cargo CRITICAL PATCH Act Now

wasmtime is a fast and secure runtime for WebAssembly. Rated critical severity (CVSS 9.9), this vulnerability is remotely exploitable, low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.

Buffer Overflow Information Disclosure Wasmtime Cranelift Codegen Bytecodealliance
NVD GitHub
CVSS 3.1
9.9
EPSS
1.3%
CVE-2022-39394 Nov 10, 20:15 Cargo CRITICAL PATCH Act Now

Wasmtime is a standalone runtime for WebAssembly. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Out-of-bounds Write vulnerability could allow attackers to write data beyond allocated buffer boundaries leading to code execution or crashes.

Buffer Overflow Memory Corruption Wasmtime Bytecodealliance
NVD GitHub
CVSS 3.1
9.8
EPSS
0.3%
CVE-2022-39393 Nov 10, 20:15 Cargo HIGH PATCH This Week

Wasmtime is a standalone runtime for WebAssembly. Rated high severity (CVSS 8.6), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub
CVSS 3.1
8.6
EPSS
0.7%
CVE-2022-39392 Nov 10, 20:15 Cargo HIGH PATCH This Week

Wasmtime is a standalone runtime for WebAssembly. Rated high severity (CVSS 7.4), this vulnerability is remotely exploitable, no authentication required. This Buffer Overflow vulnerability could allow attackers to corrupt memory to execute arbitrary code or crash the application.

Buffer Overflow Wasmtime Bytecodealliance
NVD GitHub
CVSS 3.1
7.4
EPSS
0.6%
CVE-2022-31169 Jul 22, 04:15 Cargo HIGH PATCH This Week

Wasmtime is a standalone runtime for WebAssembly. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

Information Disclosure Wasmtime Cranelift Codegen Bytecodealliance
NVD GitHub
CVSS 3.1
7.5
EPSS
0.7%
CVE-2022-31146 Jul 21, 04:15 Cargo HIGH PATCH This Week

Wasmtime is a standalone runtime for WebAssembly. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.

Information Disclosure Use After Free Memory Corruption Wasmtime Cranelift Codegen +1
NVD GitHub
CVSS 3.1
8.8
EPSS
0.9%
CVE-2022-31104 Jun 28, 00:15 Cargo MEDIUM PATCH This Month

Wasmtime is a standalone runtime for WebAssembly. Rated medium severity (CVSS 5.6), this vulnerability is remotely exploitable, no authentication required.

Information Disclosure Wasmtime Cranelift Codegen Bytecodealliance
NVD GitHub
CVSS 3.1
5.6
EPSS
1.6%
CVE-2022-24791 Mar 31, 23:15 Cargo CRITICAL PATCH Act Now

Wasmtime is a standalone JIT-style runtime for WebAssembly, using Cranelift. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.

Denial Of Service Use After Free Memory Corruption Wasmtime Bytecodealliance
NVD GitHub
CVSS 3.1
9.8
EPSS
1.1%
CVE-2021-43790 Nov 30, 00:15 Cargo HIGH POC PATCH This Week

Lucet is a native WebAssembly compiler and runtime. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, no authentication required. Public exploit code available.

Buffer Overflow Use After Free Memory Corruption Lucet Bytecodealliance
NVD GitHub
CVSS 3.1
8.1
EPSS
1.6%
CVE-2021-39218 Sep 17, 21:15 LIB MEDIUM PATCH This Month

Wasmtime is an open source runtime for WebAssembly & WASI. Rated medium severity (CVSS 6.3). This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.

Buffer Overflow Information Disclosure Fedora Wasmtime Bytecodealliance +1
NVD GitHub
CVSS 3.1
6.3
EPSS
0.3%
CVE-2021-39219 Sep 17, 20:15 LIB MEDIUM PATCH This Month

Wasmtime is an open source runtime for WebAssembly & WASI. Rated medium severity (CVSS 6.3). This Access of Resource Using Incompatible Type (Type Confusion) vulnerability could allow attackers to execute arbitrary code by exploiting type confusion in the application.

Information Disclosure Memory Corruption Fedora Wasmtime Bytecodealliance +1
NVD GitHub
CVSS 3.1
6.3
EPSS
0.4%
CVE-2021-39216 Sep 17, 20:15 LIB MEDIUM PATCH This Month

Wasmtime is an open source runtime for WebAssembly & WASI. Rated medium severity (CVSS 6.3). No vendor patch available.

Information Disclosure Use After Free Memory Corruption Fedora Wasmtime +2
NVD GitHub
CVSS 3.1
6.3
EPSS
0.3%
CVE-2021-32629 May 24, 16:15 LIB HIGH POC PATCH This Week

Cranelift is an open-source code generator maintained by Bytecode Alliance. Rated high severity (CVSS 8.8), this vulnerability is low attack complexity. Public exploit code available.

Information Disclosure Cranelift Codegen Bytecodealliance
NVD GitHub
CVSS 3.1
8.8
EPSS
0.5%
EPSS 0% CVSS 2.3
LOW PATCH Monitor

Resource exhaustion in Wasmtime's native WASIp1 implementation allows low-privileged WebAssembly guests to exhaust host-level file descriptors and OS resources by repeatedly invoking fd_renumber in a loop. The affected versions span four distinct release branches - all pre-24.0.10, 25.x-35.x, 37.x-44.x, and 45.0.0-45.0.1 - but only runtimes that both expose fd_renumber and grant guests the ability to open files are vulnerable. No public exploit code exists and the issue is not listed in CISA KEV; however, the attack is mechanically straightforward once the conditions are met, making patching the primary defense.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub
EPSS 0% CVSS 6.1
MEDIUM PATCH This Month

Wasmtime prior to versions 24.0.7, 36.0.7, 42.0.2, and 43.0.1 allows authenticated remote attackers to corrupt memory by providing malicious realloc return values during string transcoding between WebAssembly components, enabling writes to arbitrary memory locations up to 4GiB away from linear memory base. On default configurations with 4GiB virtual memory reservation and guard pages, exploitation typically triggers process abort via unmapped memory access; however, configurations with reduced memory reservation and disabled guard pages risk corruption of host data structures or other guest linear memories.

Buffer Overflow Memory Corruption Red Hat +3
NVD GitHub VulDB
EPSS 0% CVSS 6.1
MEDIUM PATCH This Month

Wasmtime versions 25.0.0 through 36.0.6, 42.0.0-42.0.1, and 43.0.0 contain a compiler type-checking bug in the Winch backend where the table.grow operator returns incorrectly typed 64-bit values instead of 32-bit values for 32-bit tables, enabling read/write access to 16 bytes of host memory preceding linear memory and resulting in denial of service when Wasmtime detects the unauthorized access. The vulnerability requires explicit selection of the non-default Winch compiler backend and either disabled guard pages or modified memory layout to achieve information disclosure; default Wasmtime configurations using the Cranelift compiler and standard guard page placement are unaffected. No public exploit code or active exploitation has been identified, though the attack vector is remote and requires low-privilege authenticated access.

Denial Of Service Red Hat Wasmtime +2
NVD GitHub VulDB
EPSS 0% CVSS 2.3
LOW PATCH Monitor

Wasmtime's pooling allocator leaks linear memory contents between WebAssembly instances when configured with specific non-default settings (memory_guard_size=0, memory_reservation<4GiB, max_memory_size=memory_reservation). Affected versions 28.0.0 through 36.0.6, 42.0.0-42.0.1, and 43.0.0 allow authenticated local attackers with high attack complexity to read sensitive data from previously-mapped memory due to incorrect virtual memory permission reset logic. Vendor-released patches: 36.0.7, 42.0.2, and 43.0.1. No public exploit identified at time of analysis.

Buffer Overflow Wasmtime Bytecodealliance
NVD GitHub VulDB
EPSS 0% CVSS 9.0
CRITICAL PATCH Act Now

Memory sandbox escape in Wasmtime's Winch compiler (versions 25.0.0 to before 36.0.7, 42.0.2, 43.0.1) enables authenticated WebAssembly guests to access arbitrary host process memory outside linear-memory boundaries. Exploitation requires non-default Winch backend activation via -Ccompiler=winch flag. Attackers can read up to 32KiB before memory start or ~4GiB after, with theoretical potential for unlimited in-process memory access due to improper 32-bit offset handling in 64-bit registers. Consequences include host process crashes (DoS), sensitive data exfiltration, or remote code execution through memory writes. Affects aarch64 (confirmed PoC) and x86-64 (theoretical). Publicly available exploit code exists.

Buffer Overflow Information Disclosure Red Hat +3
NVD GitHub VulDB
EPSS 0% CVSS 1.0
LOW PATCH Monitor

Wasmtime 43.0.0 contains a use-after-free vulnerability in the Linker cloning mechanism that allows host embedders to trigger memory corruption through a specific sequence of API calls: cloning a wasmtime::Linker, dropping the original instance, and then using the cloned instance. This vulnerability is not exploitable by guest WebAssembly programs and requires deliberate misuse of the host API. The flaw is fixed in Wasmtime 43.0.1. Despite the use-after-free nature (CWE-416), the CVSS 4.0 score of 1.0 reflects the extremely limited attack surface: physical or local access is required (AV:P), attack complexity is high (AC:H), high privilege level is needed (PR:H), and user interaction is required (UI:A), resulting in minimal confidentiality, integrity, and availability impact.

Information Disclosure Use After Free Memory Corruption +2
NVD GitHub VulDB
EPSS 0% CVSS 9.0
CRITICAL PATCH Act Now

Arbitrary memory read/write vulnerability in Bytecode Alliance Wasmtime versions 32.0.0 through 36.0.6, 42.0.0-42.0.1, and 43.0.0 allows authenticated remote attackers to escape WebAssembly sandbox restrictions. The Cranelift compilation backend on aarch64 architecture miscompiles specific heap access patterns, creating divergent address computations where bounds checks validate one address while loads access another, enabling sandbox escape through unrestricted host memory access. Exploitation requires 64-bit WebAssembly linear memories with Spectre mitigations and signals-based-traps disabled. No public exploit identified at time of analysis.

Buffer Overflow Information Disclosure Wasmtime +1
NVD GitHub VulDB
EPSS 0% CVSS 5.9
MEDIUM PATCH This Month

Wasmtime's Winch compiler (versions 25.0.0 through 36.0.6, 42.0.0-42.0.1, and 43.0.0) contains a table indexing vulnerability in the table.fill instruction that causes host panic when compiled by Winch on any architecture. A valid WebAssembly guest can trigger this denial-of-service condition due to incorrect table reference indexing left behind after a historical refactoring. EPSS score of 5.9 reflects medium exploitability, and the vulnerability is patched in Wasmtime 36.0.7, 42.0.2, and 43.0.1.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub VulDB
EPSS 0% CVSS 2.3
LOW PATCH Monitor

Wasmtime's Winch compiler in versions 25.0.0 through 36.0.6, 42.0.1, and 43.0.0 incorrectly translates the WebAssembly table.size instruction for 64-bit tables under the memory64 proposal, allowing WebAssembly guests to read sensitive data from the host's stack. The vulnerability stems from static typing the return value as 32-bit instead of consulting the table's actual index type, which when combined with Winch's multi-value return ABI mechanics enables stack data disclosure. This is fixed in Wasmtime 36.0.7, 42.0.2, and 43.0.1; no public exploit code or active exploitation has been identified at time of analysis, but the low CVSS score (2.3) reflects limited real-world impact due to authentication requirements and limited technical scope.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub VulDB
EPSS 0% CVSS 4.1
MEDIUM PATCH This Month

Wasmtime's Cranelift compiler generates inefficient code for the f64x2.splat WebAssembly instruction on x86-64 platforms with SSE3 disabled, causing it to load 8 excess bytes beyond the intended operand. On systems with signals-based traps disabled, this overflow access can trigger segmentation faults from unmapped guard pages; with guard pages also disabled, out-of-sandbox memory is accessible to the runtime (though not to WebAssembly guests themselves). The vulnerability affects Wasmtime versions prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, and is fixed in those releases. No public exploit code or active exploitation (KEV) is documented.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub VulDB
EPSS 0% CVSS 5.6
MEDIUM PATCH This Month

Wasmtime runtime before versions 24.0.7, 36.0.7, 42.0.2, and 43.0.1 panics when lifting component model flags-typed values with out-of-specification bit patterns, enabling guest-controlled denial-of-service in the host environment. The vulnerability requires high privilege and user interaction but affects a critical WebAssembly runtime used in production systems. No public exploit code is confirmed at time of analysis.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub VulDB
EPSS 0% CVSS 5.9
MEDIUM PATCH This Month

Wasmtime prior to versions 24.0.7, 36.0.7, 42.0.2, and 43.0.1 fails to properly validate pointer alignment when transcoding strings into UTF-16 or Latin-1+UTF-16 encodings within the Component Model, allowing authenticated malicious WebAssembly guests to trigger host panics by passing specially crafted unaligned pointers across component boundaries. This denial-of-service vulnerability requires authenticated access and specific string configurations but results in controllable host crashes. CVSS score 5.9 reflects moderate severity with attack vector network and authentication requirement; SSVC framework rates exploitation as not yet observed with non-automatable exploitation.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub VulDB
EPSS 0% CVSS 6.9
MEDIUM PATCH This Month

Wasmtime runtime versions prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1 incorrectly validate UTF-16 string byte lengths during component-model encoding transcoding, causing out-of-bounds memory reads that trigger process termination via segfault in default configurations or potentially expose host memory when guard pages are disabled. Authenticated users with UI interaction can trigger this denial-of-service vulnerability; reading beyond linear memory requires non-standard Wasmtime configuration without guard pages. No public exploit code has been identified at time of analysis.

Buffer Overflow Information Disclosure Wasmtime +1
NVD GitHub VulDB
EPSS 0% CVSS 7.5
HIGH PATCH This Week

Wasmtime's HTTP header handling in the wasmtime-wasi-http crate crashes when processing excessive header fields, allowing remote attackers to trigger denial of service against applications embedding Wasmtime. The vulnerability affects versions prior to 24.0.6, 36.0.6, 40.0.4, 41.0.4, and 42.0.0, and has been patched to return a controlled trap instead of panicking. Embedders should update immediately to mitigate this DoS vector.

Denial Of Service Industrial Red Hat +2
NVD GitHub
EPSS 0% CVSS 6.5
MEDIUM PATCH This Month

Uncontrolled resource allocation in Wasmtime's WASI host interfaces allows authenticated guests to trigger denial of service on the host system by exhausting resources without proper limits. Affected versions prior to 24.0.6, 36.0.6, 40.0.4, 41.0.4, and 42.0.0 require explicit configuration to mitigate this issue, though Wasmtime 42.0.0 and later provide secure defaults. No patch is currently available for older versions, and resource exhaustion protections must be manually enabled.

Denial Of Service Red Hat Wasmtime +1
NVD GitHub
EPSS 0% CVSS 7.5
HIGH PATCH This Week

Wasmtime versions 39.0.0 and later experience a denial-of-service panic when async WebAssembly component functions are called and then abandoned by the host before completion, such as when the Future is dropped after a single poll during an async yield. This affects applications using Wasmtime's component model with async support, allowing an attacker to crash the runtime through specially crafted async function invocations. A patch is available to address this stability issue.

Golang Industrial Red Hat +2
NVD GitHub
EPSS 0% CVSS 5.5
MEDIUM PATCH This Month

Wasmtime versions 29.0.0 through 41.0.0 on x86-64 platforms with AVX contain an out-of-bounds memory read in the f64.copysign instruction compilation that can cause application crashes when signal-based traps are disabled. In configurations with disabled guard pages, this vulnerability could potentially leak out-of-sandbox data, though the data remains inaccessible to WebAssembly guests without additional Cranelift bugs. Patches are available in versions 36.0.5, 40.0.3, and 41.0.1.

Buffer Overflow Information Disclosure Wasmtime +1
NVD GitHub
EPSS 0% CVSS 5.1
MEDIUM POC This Month

WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (Wasm) runtime. Rated medium severity (CVSS 5.1), this vulnerability is no authentication required. Public exploit code available and no vendor patch available.

Buffer Overflow Webassembly Micro Runtime Bytecodealliance
NVD GitHub
EPSS 0% CVSS 4.7
MEDIUM POC This Month

WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (Wasm) runtime. Rated medium severity (CVSS 4.7), this vulnerability is no authentication required. Public exploit code available and no vendor patch available.

Information Disclosure Webassembly Micro Runtime Bytecodealliance
NVD GitHub
EPSS 0% CVSS 2.1
LOW POC PATCH Monitor

WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (Wasm) runtime. Rated low severity (CVSS 2.1), this vulnerability is no authentication required, low attack complexity. Public exploit code available.

Denial Of Service Integer Overflow Webassembly Micro Runtime +1
NVD GitHub
EPSS 0% CVSS 7.0
HIGH POC PATCH This Month

The WebAssembly Micro Runtime's (WAMR) iwasm package is the executable binary built with WAMR VMcore which supports WebAssembly System Interface (WASI) and command line interface. Rated high severity (CVSS 7.0), this vulnerability is no authentication required, low attack complexity. Public exploit code available.

Windows Information Disclosure Microsoft +2
NVD GitHub
EPSS 0% CVSS 7.5
HIGH POC This Week

wasm-micro-runtime (aka WebAssembly Micro Runtime or WAMR) 06df58f is vulnerable to NULL Pointer Dereference in function `block_type_get_result_types. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Denial Of Service Null Pointer Dereference Webassembly Micro Runtime +1
NVD GitHub
EPSS 1% CVSS 7.8
HIGH POC PATCH This Week

An issue in bytecodealliance wasm-micro-runtime before v.b3f728c and fixed in commit 06df58f allows a remote attacker to escalate privileges via a crafted file to the check_was_abi_compatibility. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. Public exploit code available.

Buffer Overflow Information Disclosure Webassembly Micro Runtime +1
NVD GitHub
EPSS 1% CVSS 2.3
LOW PATCH Monitor

Wasmtime is a fast and secure runtime for WebAssembly. Rated low severity (CVSS 2.3), this vulnerability is remotely exploitable, low attack complexity.

Authentication Bypass Microsoft Wasmtime +1
NVD GitHub
EPSS 0% CVSS 2.9
LOW PATCH Monitor

Wasmtime is an open source runtime for WebAssembly. Rated low severity (CVSS 2.9). No vendor patch available.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub
EPSS 0% CVSS 5.5
MEDIUM PATCH This Month

Wasmtime is an open source runtime for WebAssembly. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity.

Denial Of Service Google Wasmtime +1
NVD GitHub
EPSS 1% CVSS 7.5
HIGH POC This Week

An out-of-bound memory read vulnerability was discovered in Bytecode Alliance wasm-micro-runtime v2.0.0 which allows a remote attacker to cause a denial of service via the "block_type_get_arity". Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Buffer Overflow Denial Of Service Information Disclosure +2
NVD GitHub
EPSS 0% CVSS 6.2
MEDIUM POC This Month

A heap buffer overflow vulnerability was discovered in Bytecode Alliance wasm-micro-runtime v2.0.0 which allows a remote attacker to cause at least a denial of service via the "wasm_loader_check_br". Rated medium severity (CVSS 6.2), this vulnerability is no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Buffer Overflow Denial Of Service Heap Overflow +2
NVD GitHub
EPSS 0% CVSS 5.5
MEDIUM POC PATCH This Month

wasmtime is a runtime for WebAssembly. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. Public exploit code available.

Information Disclosure Memory Corruption Wasmtime +1
NVD GitHub
EPSS 0% CVSS 5.5
MEDIUM POC PATCH This Month

Bytecode Alliance wasm-micro-runtime (aka WebAssembly Micro Runtime or WAMR) before 1.3.0 can have an "double free or corruption" error for a valid WebAssembly module because. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, low attack complexity. Public exploit code available.

Information Disclosure Webassembly Micro Runtime Bytecodealliance
NVD GitHub
EPSS 1% CVSS 7.5
HIGH POC PATCH This Week

An heap overflow vulnerability was discovered in Bytecode alliance wasm-micro-runtime v.1.2.3 allows a remote attacker to cause a denial of service via the wasm_loader_prepare_bytecode function in. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

Buffer Overflow Denial Of Service Memory Corruption +2
NVD GitHub VulDB
EPSS 1% CVSS 5.3
MEDIUM PATCH This Month

Wasmtime is a standalone runtime for WebAssembly. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub
EPSS 0% CVSS 8.8
HIGH PATCH This Week

Wasmtime is a standalone runtime for WebAssembly. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub
EPSS 1% CVSS 4.3
MEDIUM PATCH This Month

wasmtime is a fast and secure runtime for WebAssembly. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity.

Information Disclosure Wasmtime Cranelift Codegen +1
NVD GitHub
EPSS 1% CVSS 9.9
CRITICAL PATCH Act Now

wasmtime is a fast and secure runtime for WebAssembly. Rated critical severity (CVSS 9.9), this vulnerability is remotely exploitable, low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.

Buffer Overflow Information Disclosure Wasmtime +2
NVD GitHub
EPSS 0% CVSS 9.8
CRITICAL PATCH Act Now

Wasmtime is a standalone runtime for WebAssembly. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Out-of-bounds Write vulnerability could allow attackers to write data beyond allocated buffer boundaries leading to code execution or crashes.

Buffer Overflow Memory Corruption Wasmtime +1
NVD GitHub
EPSS 1% CVSS 8.6
HIGH PATCH This Week

Wasmtime is a standalone runtime for WebAssembly. Rated high severity (CVSS 8.6), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

Information Disclosure Wasmtime Bytecodealliance
NVD GitHub
EPSS 1% CVSS 7.4
HIGH PATCH This Week

Wasmtime is a standalone runtime for WebAssembly. Rated high severity (CVSS 7.4), this vulnerability is remotely exploitable, no authentication required. This Buffer Overflow vulnerability could allow attackers to corrupt memory to execute arbitrary code or crash the application.

Buffer Overflow Wasmtime Bytecodealliance
NVD GitHub
EPSS 1% CVSS 7.5
HIGH PATCH This Week

Wasmtime is a standalone runtime for WebAssembly. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

Information Disclosure Wasmtime Cranelift Codegen +1
NVD GitHub
EPSS 1% CVSS 8.8
HIGH PATCH This Week

Wasmtime is a standalone runtime for WebAssembly. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.

Information Disclosure Use After Free Memory Corruption +3
NVD GitHub
EPSS 2% CVSS 5.6
MEDIUM PATCH This Month

Wasmtime is a standalone runtime for WebAssembly. Rated medium severity (CVSS 5.6), this vulnerability is remotely exploitable, no authentication required.

Information Disclosure Wasmtime Cranelift Codegen +1
NVD GitHub
EPSS 1% CVSS 9.8
CRITICAL PATCH Act Now

Wasmtime is a standalone JIT-style runtime for WebAssembly, using Cranelift. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.

Denial Of Service Use After Free Memory Corruption +2
NVD GitHub
EPSS 2% CVSS 8.1
HIGH POC PATCH This Week

Lucet is a native WebAssembly compiler and runtime. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, no authentication required. Public exploit code available.

Buffer Overflow Use After Free Memory Corruption +2
NVD GitHub
EPSS 0% CVSS 6.3
MEDIUM PATCH This Month

Wasmtime is an open source runtime for WebAssembly & WASI. Rated medium severity (CVSS 6.3). This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.

Buffer Overflow Information Disclosure Fedora +3
NVD GitHub
EPSS 0% CVSS 6.3
MEDIUM PATCH This Month

Wasmtime is an open source runtime for WebAssembly & WASI. Rated medium severity (CVSS 6.3). This Access of Resource Using Incompatible Type (Type Confusion) vulnerability could allow attackers to execute arbitrary code by exploiting type confusion in the application.

Information Disclosure Memory Corruption Fedora +3
NVD GitHub
EPSS 0% CVSS 6.3
MEDIUM PATCH This Month

Wasmtime is an open source runtime for WebAssembly & WASI. Rated medium severity (CVSS 6.3). No vendor patch available.

Information Disclosure Use After Free Memory Corruption +4
NVD GitHub
EPSS 0% CVSS 8.8
HIGH POC PATCH This Week

Cranelift is an open-source code generator maintained by Bytecode Alliance. Rated high severity (CVSS 8.8), this vulnerability is low attack complexity. Public exploit code available.

Information Disclosure Cranelift Codegen Bytecodealliance
NVD GitHub

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