Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:LSummary
CVE-2026-6751 is a high-severity Use of Uninitialized Variable (CWE-457) vulnerability in Mozilla Firefox. Its CVSS base score is 7.3 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 23th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-6751 is an uninitialized memory vulnerability (CWE-457) in the Audio/Video: Web Codecs component of Mozilla Firefox and Thunderbird products. It affects versions prior to Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10. The issue was publicly disclosed on 2026-04-21 and carries a CVSS v3.1 base score of 7.3 (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L), indicating high severity due to its network accessibility and lack of prerequisites for exploitation.
Remote attackers can exploit this vulnerability without authentication or user interaction by targeting the Web Codecs API, potentially leading to limited disclosure of sensitive information, minor integrity modifications, or partial denial of service through memory corruption. The unchanged scope suggests impacts remain within the affected browser process.
Mozilla's security advisories (MFSA 2026-30 through 2026-34) and the associated Bugzilla entry detail the fix applied in the specified versions, recommending immediate upgrades to patched releases for mitigation. No workarounds are mentioned in the provided references.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-24092
Vulnerability Data
Uninitialized memory in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and static analysis directly find uses of uninitialized variables before deployment.
Documented development standards and tools can enforce initialization requirements in code.
Engineering principles can mandate explicit variable initialization to avoid uninitialized use.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly catch uninitialized-variable defects via static analysis and code review while the control encompasses many additional development controls.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect uninitialized-variable bugs, but the control is broader.
Secure development life cycle mandates practices that reduce uninitialized-variable defects.
Application security requirements can specify initialization rules, but the control itself does not directly address the weakness.
Secure architecture principles discourage unsafe pointer handling.
Secure coding explicitly requires variable initialization and static-analysis checks.