Heap buffer overflow via re-entrant prototype getter
Published Jan 10, 2026 · Updated Jan 10, 2026
Heap buffer overflow in QuickJS-NG QuickJS 0.11.0 and earlier allows attackers to read out-of-bounds heap data via crafted JavaScript. js_typed_array_constructor invokes a prototype getter that can resize or detach its input ArrayBuffer before typed_array_init uses stale bounds. Exploitation requires an embedding or qjs invocation that executes attacker-controlled JavaScript; the published proof of concept demonstrates an out-of-bounds read under AddressSanitizer.
Summary
What happened
Heap buffer overflow in QuickJS-NG QuickJS 0.11.0 and earlier allows attackers to read out-of-bounds heap data via crafted JavaScript. js_typed_array_constructor invokes a prototype getter that can resize or detach its input ArrayBuffer before typed_array_init uses stale bounds. Exploitation requires an embedding or qjs invocation that executes attacker-controlled JavaScript; the published proof of concept demonstrates an out-of-bounds read under AddressSanitizer.
The record
- CVE
- CVE-2026-0821
- Published
- Jan 10, 2026
- Updated
- Jan 10, 2026
- Vendor
- QuickJS-NG
- Product
- QuickJS
- Classifications
- CWE-122, CWE-119
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 10, 2026CVE publishedPublication date reported by the CVE source.
- Jan 10, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0.1
- Affected versionversion=0.10
- Affected versionversion=0.11.0
- Affected versionversion=0.2
- Affected versionversion=0.3
- Affected versionversion=0.4
- Affected versionversion=0.5
- Affected versionversion=0.6
- Affected versionversion=0.7
- Affected versionversion=0.8
- Affected versionversion=0.9
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- js_typed_array_constructor ArrayBuffer-resize proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo