What is the CVSS score of EUVD-2026-25587?

EUVD-2026-25587 has a CVSS 4.0 base score of 8.3 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N. EPSS exploitation probability: 0.0%.

How to fix or mitigate EUVD-2026-25587?

Within 24 hours: Inventory all applications and services using rust-openssl and identify those running versions 0.9.24-0.10.77. Within 7 days: Upgrade rust-openssl to version 0.10.78 or later across all affected systems and redeploy applications. Within 30 days: Conduct security testing on upgraded systems and document remediation completion in your vulnerability management system.

rust-openssl EUVD-2026-25587

Q: Which versions of rust-openssl are affected by EUVD-2026-25587?

rust-openssl versions 0.9.24 through 0.10.77 contain a buffer overflow vulnerability that allows remote attackers to cause memory corruption and potential data breaches through malformed PSK or…. A patch is available.

| CVE-2026-41898 HIGH

Buffer Over-read (CWE-126)

2026-04-24 GitHub_M

GHSA-hppc-g8h3-xhp3

Buffer Overflow OpenSSL Suse Rust Openssl

8.3

CVSS 4.0 · Vendor: GitHub_M

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Initiate TLS/DTLS connection
Delivery

Send crafted PSK/cookie request
Exploit

Trigger callback with oversized return
Execution

OpenSSL reads beyond buffer
Impact

Expose heap memory or crash process

Vulnerability Assessment

Weakness	CWE CWE-126 ASVS 5.0 V15 - Secure Coding and Architecture Buffer over-read prevention
Exploitation Conditions	Exploitation requires the target Rust application to use rust-openssl versions 0.9.24-0.10.77 AND explicitly configure at least one of four specific callback types: PSK client callbacks (set_psk_client_callback), PSK server callbacks (set_psk_server_callback), DTLS cookie generation callbacks (set_cookie_generate_cb), or stateless cookie callbacks (set_stateless_cookie_generate_cb). The application's callback closure implementation must also contain a logic bug that returns a usize value exceeding the &mut [u8] slice length provided to it. Attack vector is network-based (AV:N) with no authentication required (PR:N), but success depends on precise timing conditions (AT:P) to trigger the vulnerable code path during TLS/DTLS handshake negotiation. Applications using only default certificate-based TLS authentication without PSK configuration are not exploitable. The vulnerability is also limited to platforms where heap memory layout allows adjacent sensitive data disclosure, making impact severity variable across deployment environments.
Impact	Real-world risk is moderate despite the 8.3 CVSS score. The CVSS:4.0 vector shows network-reachable exploitation (AV:N) with low attack complexity (AC:L) but requires precise timing or race conditions (AT:P), indicating the attacker must control callback timing or server state to reliably trigger the overflow. High confidentiality impact (VC:H) suggests potential memory disclosure of cryptographic material or session data, while low availability impact (VA:L) indicates crashes rather than sustained denial of service. Critically, SSVC framework reports no active exploitation (Exploitation: none) and non-automatable attacks (Automatable: no), meaning this requires targeted development against specific rust-openssl deployments using PSK or cookie callbacks. The vulnerability only manifests in applications that: (1) use rust-openssl for TLS/DTLS, (2) explicitly configure PSK authentication or stateless cookie callbacks, and (3) provide closures with logic bugs that return incorrect buffer sizes. Default TLS configurations using certificate-based authentication are unaffected. Patch availability in version 0.10.78 significantly reduces window of exposure. Priority should be medium for organizations using PSK-based TLS in Rust applications, low for standard certificate-based deployments.
Exploit ScenarioDerived	An attacker establishes a TLS connection to a Rust application server using PSK authentication with a vulnerable rust-openssl version. During the PSK callback phase, the attacker sends a crafted Client Hello requesting a PSK identity that triggers the application's set_psk_server_callback closure. If the closure contains a logic error that returns a buffer size larger than the allocated slice (e.g., returning a hardcoded constant instead of actual data length), the FFI trampoline passes this unchecked value to OpenSSL, causing OpenSSL to read beyond the buffer boundary into adjacent heap memory. This exposes cryptographic key material or session tokens in the confidentiality breach (VC:H), and may cause a segmentation fault leading to process crash (VA:L). Public exploit code availability not confirmed at time of analysis, but attack requires detailed knowledge of target application's callback implementation and precise timing to win race conditions (AT:P).

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Apr 24, 2026

Buffer overflow in rust-openssl 0.9.24 through 0.10.77 allows remote unauthenticated attackers to trigger memory corruption via crafted PSK (Pre-Shared Key) or cookie callback responses. The FFI trampolines in SslContextBuilder fail to validate closure-returned buffer sizes against allocated memory regions before passing values to OpenSSL, enabling out-of-bounds writes. Patch released in version 0.10.78. SSVC framework indicates no active exploitation detected, non-automatable attack requiring precise timing conditions (CVSS AT:P), with partial technical impact limited to confidentiality breach and minor availability disruption.

RemediationAI

Upgrade rust-openssl to version 0.10.78 or later, released with fix commit 1d109020d98fff2fb2e45c39a373af3dff99b24c (see https://github.com/rust-openssl/rust-openssl/releases/tag/openssl-v0.10.78 and PR https://github.com/rust-openssl/rust-openssl/pull/2607). Update Cargo.toml dependency to openssl = "0.10.78" and run cargo update. For applications unable to upgrade immediately, implement compensating controls by auditing all SslContextBuilder callback closures to ensure returned usize values never exceed the length of the provided &mut [u8] slice, adding explicit bounds checks like return callback_data.len().min(buffer.len()) before returning buffer sizes. Alternative mitigation: disable PSK cipher suites in TLS configuration if not required for business logic, forcing certificate-based authentication only, though this may break compatibility with embedded/IoT devices expecting PSK. Note that disabling callbacks entirely eliminates attack surface but removes PSK and stateless DTLS functionality. Test callback logic thoroughly after applying workarounds, as overly restrictive bounds checking may cause TLS handshake failures.

Affected VersionsENISA

rust-openssl 0.9.24, < 0.10.78

Affected Packages

cargo openssl fix: 0.10.78

euvd rust_openssl_0_9_24 fix: 0.10.78

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 2 packages in cargo, euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

rust-openssl is a Rust language binding library providing safe FFI (Foreign Function Interface) wrappers around OpenSSL cryptographic functions. The vulnerability resides in four callback registration methods within SslContextBuilder: set_psk_client_callback, set_psk_server_callback, set_cookie_generate_cb, and set_stateless_cookie_generate_cb. These methods create FFI trampolines that bridge Rust closures to C-compatible OpenSSL callbacks. The root cause (CWE-126: Buffer Over-read) occurs when the trampoline forwards the usize return value from user-provided closures directly to OpenSSL without bounds-checking it against the mutable byte slice (&mut [u8]) passed to the closure. This violates Rust's memory safety guarantees at the FFI boundary, allowing the closure to specify arbitrary buffer lengths that exceed allocated memory regions, resulting in buffer overflows when OpenSSL attempts to read or write beyond valid boundaries. The affected CPE (cpe:2.3:a:rust-openssl:rust-openssl) spans versions 0.9.24 through 0.10.77, covering approximately two years of releases.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (GitHub_M) PRIMARY 8.3 HIGH

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N

SUSE 6.5 MEDIUM

AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:L

Primary rating from Vendor (GitHub_M).

CVSS VectorVendor: GitHub_M

Attack Vector

Network

Attack Complexity

Low

Attack Requirements

Present

Privileges Required

None

User Interaction

None

Vulnerable system: Confidentiality

High

Vulnerable system: Integrity

None

Vulnerable system: Availability

Low

Subsequent system: Confidentiality

None

Subsequent system: Integrity

None

Subsequent system: Availability

None

Lifecycle Timeline

Patch released

Apr 28, 2026 - 17:45 nvd

Patch available

Apr 24, 2026 - 19:01 EUVD

CVSS changed

Apr 24, 2026 - 18:22 NVD

8.3 (HIGH)

CVE Published

Apr 24, 2026 - 17:20 nvd

HIGH 8.3

DescriptionCVE.org

rust-openssl provides OpenSSL bindings for the Rust programming language. From 0.9.24 to before 0.10.78, the FFI trampolines behind SslContextBuilder::set_psk_client_callback, set_psk_server_callback, set_cookie_generate_cb, and set_stateless_cookie_generate_cb forwarded the user closure's returned usize directly to OpenSSL without checking it against the &mut [u8] that was handed to the closure. This can lead to buffer overflows and other unintended consequences. This vulnerability is fixed in 0.10.78.

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

352 cargo packages depend on openssl (62 direct, 290 indirect)

Ecosystem-wide dependent count for version 0.9.24.

Executive ViewAI

Why It Matters

rust-openssl versions 0.9.24 through 0.10.77 contain a buffer overflow vulnerability that allows remote attackers to cause memory corruption and potential data breaches through malformed PSK or cookie responses. This affects any application using the vulnerable library versions for TLS/SSL communications, requiring immediate remediation to prevent unauthorized access to sensitive data handled by affected services.

Business Impact: High

Compensating Controls

Vendor-released patch: rust-openssl 0.10.78. Apply immediately upon release validation. If immediate patching is infeasible, restrict network exposure of affected services to trusted networks only and implement network-based rate limiting on TLS connection attempts to increase attack complexity.

Threat Intelligence Overview

EPSS Score

0.0%

Top 87% exploitable

Threat Intel

1 source

Data Quality

7 sources

Confidence: High

EUVD

NVD

CVE.org

EPSS

Vulnrichment GHSA Vendor

GitHub

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC No

EPSS 0.0%

Patch available Yes

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision

Scheduled

Exploitation

None

System Exposure· derived

Open

Automatable

Human Impact

High

Technical Impact

Partial

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +42

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Buffer Overflow HIGH

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

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Severity: Moderate

Product	Status
Container suse/sl-micro/6.0/baremetal-os-container:latest	Affected
Container suse/sl-micro/6.0/toolbox:latest	Affected
Image SLES15-SP7-Azure-3P Image SLES15-SP7-Azure-Basic Image SLES15-SP7-Azure-Standard Image SLES15-SP7-BYOS-Azure Image SLES15-SP7-BYOS-GCE Image SLES15-SP7-CHOST-BYOS-Aliyun Image SLES15-SP7-CHOST-BYOS-Azure Image SLES15-SP7-CHOST-BYOS-EC2 Image SLES15-SP7-CHOST-BYOS-GDC Image SLES15-SP7-CHOST-BYOS-SAP-CCloud Image SLES15-SP7-EC2 Image SLES15-SP7-EC2-ECS-HVM Image SLES15-SP7-GCE Image SLES15-SP7-HPC-Azure Image SLES15-SP7-HPC-BYOS-Azure Image SLES15-SP7-HPC-BYOS-EC2 Image SLES15-SP7-HPC-BYOS-GCE Image SLES15-SP7-Hardened-BYOS-Azure Image SLES15-SP7-Hardened-BYOS-EC2 Image SLES15-SP7-Hardened-BYOS-GCE Image SLES15-SP7-SAP-Azure Image SLES15-SP7-SAP-Azure-3P Image SLES15-SP7-SAP-BYOS-Azure Image SLES15-SP7-SAP-BYOS-EC2 Image SLES15-SP7-SAP-BYOS-GCE Image SLES15-SP7-SAP-EC2 Image SLES15-SP7-SAP-GCE Image SLES15-SP7-SAP-Hardened-Azure Image SLES15-SP7-SAP-Hardened-BYOS-Azure Image SLES15-SP7-SAP-Hardened-BYOS-EC2 Image SLES15-SP7-SAP-Hardened-BYOS-GCE Image SLES15-SP7-SAP-Hardened-GCE Image SLES15-SP7-SAPCAL-Azure Image SLES15-SP7-SAPCAL-EC2 Image SLES15-SP7-SAPCAL-GCE	Affected
SUSE Linux Enterprise Desktop 15 SP7	Fixed
SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS	Fixed

References

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