Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-6783 is a medium-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Mozilla Firefox. Its CVSS base score is 5.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique LSA Secrets (T1003.004); ranked at the 30th 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-8 (Security and Privacy Engineering Principles) — 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-2026-6783 is an integer overflow vulnerability stemming from incorrect boundary conditions (CWE-190) in the Audio/Video Playback component of Mozilla Firefox and Thunderbird. The issue allows improper handling of data during media playback processing, which was addressed in Firefox version 150 and Thunderbird version 150.
The vulnerability carries a CVSS v3.1 base score of 5.3 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N), indicating it is exploitable over the network with low complexity, requiring no privileges, no user interaction, and no change in scope. Remote unauthenticated attackers can trigger the integer overflow by supplying malicious media content, potentially leading to limited integrity impacts such as unexpected data modification without affecting confidentiality or availability.
Mozilla's security advisories (MFSA 2026-30 and MFSA 2026-33) and the associated Bugzilla entry (bug 2027564) detail the patch deployment in Firefox 150 and Thunderbird 150, recommending immediate updates to affected versions as the primary mitigation. No workarounds are specified in the provided references.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-24124
Vulnerability Data
Incorrect boundary conditions, integer overflow in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.2.6
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation (static analysis, fuzzing, unit tests) directly finds integer overflow defects before deployment.
Secure engineering principles require use of safe arithmetic constructs or language features that structurally eliminate integer overflow during calculation.
Input validation enforces bounds on values before arithmetic, stopping the conditions that trigger overflow or wraparound.
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 require use of safe arithmetic, bounds checks, and testing that prevent integer overflows.
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.