Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-2781 is a critical-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Mozilla Firefox. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique LSA Secrets (T1003.004); ranked at the 46th 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-2026-2781 is an integer overflow vulnerability (CWE-190) in the Libraries component of NSS (Network Security Services). It affects Mozilla products including Firefox versions prior to 148, Firefox ESR prior to 140.8 and 115.35, Thunderbird prior to 148 and 140.8. The vulnerability carries a CVSS v3.1 base score of 9.8, indicating critical severity due to its potential for high impact on confidentiality, integrity, and availability.
A remote attacker requires no privileges or user interaction and can exploit the vulnerability over the network with low complexity. Successful exploitation could allow the attacker to achieve high-impact effects, including unauthorized access to sensitive data, modification of system resources, and disruption of service, potentially leading to full remote code execution on affected systems.
Mozilla security advisories (MFSA 2026-13, 15, 16, 17) and the associated Bugzilla entry detail the fix applied in the specified versions of Firefox, Firefox ESR, and Thunderbird. Users should update to these patched releases to mitigate the issue.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-8502
Vulnerability Data
Integer overflow in the Libraries component in NSS. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, Thunderbird 140.8, and Firefox ESR 115.35.
- 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.