Quickjs
CVE-2026-0821
MEDIUM
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessSend crafted input to quickjs-ng parser
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ExploitTrigger js_typed_array_constructor function
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ExecutionCause heap-based buffer overflow
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ImpactExecute arbitrary code remotely
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, buffer size validation
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | No special conditions — remote unauthenticated exploitation against quickjs-ng versions up to 0.11.0 with default TypedArray handling enabled. |
| Impact | CVSS 7.3 (HIGH). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: None. Exploitable via remote/network. Public exploit/POC available. |
| Exploit ScenarioDerived | A remote attacker could exploit this vulnerability to heap-based buffer overflow. |
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Alert meAnalysisAIv1 – Mar 12, 2026
Heap-based buffer overflow in QuickJS up to version 0.11.0 within the js_typed_array_constructor function allows unauthenticated remote attackers to corrupt memory and potentially execute arbitrary code. Public exploit code exists for this vulnerability, increasing the risk of active exploitation. Affected users should apply patch c5d80831e51e48a83eab16ea867be87f091783c5 immediately.
Earlier versions of this analysis (1)
A vulnerability was determined in quickjs-ng quickjs up to 0.11.0. This vulnerability affects the function js_typed_array_constructor of the file quickjs.c. [CVSS 7.3 HIGH]
RemediationAI
A vendor patch is available — apply it immediately. Enable ASLR, DEP/NX, and stack canaries where possible. Restrict network access to the affected service where possible.
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
Classified as CWE-119 (Buffer Overflow). Affects Quickjs. A vulnerability was determined in quickjs-ng quickjs up to 0.11.0. This vulnerability affects the function js_typed_array_constructor of the file quickjs.c. Executing a manipulation can lead to heap-based buffer overflow. The attack may be launched remotely. The exploit has been publicly disclosed and may be utilized. This patch is called c5d80831e51e48a83eab16ea867be87f091783c5. A patch should be applied to remediate this issue.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
Primary rating from NVD.
CVSS VectorNVD
Lifecycle Timeline
5DescriptionCVE.org
A vulnerability was determined in quickjs-ng quickjs up to 0.11.0. This vulnerability affects the function js_typed_array_constructor of the file quickjs.c. Executing a manipulation can lead to heap-based buffer overflow. The attack may be launched remotely. The exploit has been publicly disclosed and may be utilized. This patch is called c5d80831e51e48a83eab16ea867be87f091783c5. A patch should be applied to remediate this issue.
Executive ViewAI
Organizations using quickjs-ng quickjs face moderate risk from CVE-2026-0821, a buffer overflow vulnerability rated CVSS 7.3. Exploitation could allow attackers to corrupt memory, crash the application, or potentially execute arbitrary code. Proof-of-concept code is publicly available, increasing the risk of exploitation. A patch is available and should be applied as part of regular vulnerability management.
Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.
Threat Intelligence Overview
NVD
CVE.org
EPSS
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.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
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.
Affected Products (CPE)CVE.org
A use-after-free in QuickJS's quickjs-libc standard library lets JavaScript code corrupt heap memory from inside the int
Use-after-free in QuickJS object-printing routines can corrupt memory when an attacker-influenced Array, Map, or Set is
QuickJS commit 2788d71 was discovered to contain a stack-overflow via the component js_proxy_isArray at quickjs.c. Rated
Heap out-of-bounds write in QuickJS's BigInt string parser can corrupt memory when an embedding application converts an
Integer overflow in QuickJS's libregexp bytecode accounting can become an out-of-bounds write when a crafted recursive r
Type confusion in QuickJS's handling of the string addition (+) operation allows local attackers to trigger out-of-bound
Information disclosure in QuickJS occurs through a floating-point precision error in TypedArray.prototype.indexOf() when
An out-of-bounds heap read in QuickJS's BigInt-to-string conversion (js_bigint_to_string1) lets script-controlled BigInt
Heap out-of-bounds write in QuickJS's bytecode deserializer (JS_ReadFunctionTag) lets a crafted serialized blob corrupt
quickjs-ng through 0.9.0 has a missing length check in JS_ReadString for a string, leading to a heap-based buffer overfl
quickjs-ng through 0.9.0 has an incorrect size calculation in JS_ReadBigInt for a BigInt, leading to a heap-based buffer
A vulnerability was found in quickjs-ng QuickJS up to 0.8.0. Rated medium severity (CVSS 5.3), this vulnerability is rem
Exploit-DB