Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:LCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-6753 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Mozilla Firefox. Its CVSS base score is 7.3 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Security Account Manager (T1003.002); ranked at the 38th 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-2026-6753 involves incorrect boundary conditions in the WebRTC component, classified under CWE-119. This vulnerability affects Mozilla Firefox versions prior to 150, Firefox ESR prior to 140.10, Thunderbird prior to 150, and Thunderbird prior to 140.10. It was published 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 low barriers to exploitation.
Remote attackers can exploit this vulnerability over the network with low attack complexity, requiring no privileges, user interaction, or special conditions. Successful exploitation allows limited impacts, including partial disclosure of sensitive information, partial modification of data, and partial denial of service.
Mozilla security advisories (MFSA 2026-30, 32, 33, and 34) and the associated Bugzilla entry (bug 2027501) detail the fix applied in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10, recommending immediate upgrades to these versions for mitigation.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-24094
Vulnerability Data
Incorrect boundary conditions in the WebRTC 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 evaluation (including fuzzing and bounds checks) finds out-of-bounds write flaws before deployment.
Requiring documented secure-development standards and tools can mandate bounds-checked coding practices that avoid the weakness.
Secure engineering principles require memory-safe design and coding that structurally avoids buffer-boundary violations.
Input validation directly enforces bounds checking that stops out-of-bounds reads/writes from being introduced or reached.
Memory protection restricts exploitation impact of buffer overflows without eliminating the underlying coding flaw.
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.
Vulnerability scanning and recording can discover out-of-bounds write flaws so they can be remediated.
Patching or replacing vulnerable software directly eliminates known instances of this coding weakness.
Secure-development practices (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.
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.
Hardening callouts derived
DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.
- No fine-grained STIG row for CWE-119, a class-level weakness. Rules are authored against its narrower children: CWE-823.