Security Resilience

CVE-2026-6764

Memory Safety in Mozilla Firefox ≤ 140.10.0

Published
21 April 2026
Modified
22 April 2026
Patch / advisory
CVSS Score v3.1 6.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
EPSS Score 0.0040 32th percentile
Risk Priority 51 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-6764 is a medium-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Mozilla Firefox. Its CVSS base score is 6.5 (Medium).

Operationally, ranked at the 32th 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-8 (Security and Privacy Engineering Principles) and SI-10 (Information Input Validation) — 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-2026-6764 is a vulnerability involving incorrect boundary conditions in the DOM: Device Interfaces component, classified under CWE-119. It affects Mozilla Firefox, Firefox ESR, and Thunderbird. The issue was addressed in Firefox version 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10. The vulnerability received a CVSS v3.1 base score of 6.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L), indicating medium severity with network accessibility, low attack complexity, no privileges or user interaction required, and impacts limited to low integrity and availability without confidentiality loss or scope change.

Remote attackers can exploit this vulnerability over the network without authentication or user interaction. Successful exploitation allows limited disruption, such as minor integrity violations (e.g., data modification) or availability issues (e.g., denial of service), but does not enable data exfiltration or broader system compromise.

Mozilla's security advisories (MFSA2026-30 through MFSA2026-34) and the associated Bugzilla entry (bug 2022162) detail the fix applied in the specified versions. Security practitioners should ensure affected products are updated to these patched releases to mitigate the risk.

EU & UK References

Vulnerability Data

Incorrect boundary conditions in the DOM: Device Interfaces component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.

CWE(s)

Related Threats

CVEs Like This One

CVE-2026-16393Same product: Mozilla Firefox
CVE-2026-7324Same product: Mozilla Firefox
CVE-2026-12300Same product: Mozilla Firefox
CVE-2024-9401Same product: Mozilla Firefox
CVE-2026-12305Same product: Mozilla Firefox
CVE-2026-92061Same product: Mozilla Firefox
CVE-2026-16361Same product: Mozilla Firefox
CVE-2026-6775Same product: Mozilla Firefox
CVE-2026-74988Same product: Mozilla Firefox
CVE-2026-8954Same product: Mozilla Firefox

Affected Assets

mozilla
firefox
≤ 140.10.0 · ≤ 150.0
mozilla
thunderbird
140.0 — 140.10.0

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

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 (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.

blocks

A.8.25 mandates secure SDLC practices (secure coding guidelines, security requirements, testing including code scans and penetration tests, developer training) that reach buffer management and can stop many buffer overruns from reaching production, but leaves a bounded remainder (e.g. flaws in non-software components, incomplete enforcement of guidelines, or post-deployment changes)

blocks

Application security requirements can specify memory-safety rules, but do not prescribe implementation details.

blocks

A.8.27 mandates security-by-design principles (e.g. least privilege, fail securely, distrust external input, hardening) plus design reviews that can catch and stop buffer-boundary errors before they reach code, but this is only one minority slice of CWE-119's broad surface (language-specific flaws, unsafe library use, compiler/runtime mitigations, and post-deployment instances remain outside its direct scope).

prevents

Secure coding standards explicitly forbid unsafe buffer operations, directly eliminating CWE-119.

finds

Security testing in development catches out-of-bounds accesses before release, covering most instances of the weakness.

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.

References