Cyber Posture

CVE-2026-8962

High

Published: 19 May 2026

Published
19 May 2026
Modified
20 May 2026
KEV Added
Patch
CVSS Score 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
EPSS Score 0.0002 4.9th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-8962 is a high-severity Protection Mechanism Failure (CWE-693) vulnerability in Mozilla Firefox. Its CVSS base score is 8.1 (High).

Operationally, ranked at the 4.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

Threat & Defense Details

Likely Mitigating ControlsAI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-693

Implements a reliable, tamperproof protection mechanism whose completeness can be assured.

addresses: CWE-693

Procedures for training on protection mechanisms reduce the chance of protection mechanism failures being present or exploitable.

addresses: CWE-693

Documented procedures to implement assessment, authorization, and monitoring controls prevent these protection mechanisms from failing due to undefined processes.

addresses: CWE-693

Direct evaluation of whether controls produce desired security outcomes detects protection mechanism failures and enables remediation.

addresses: CWE-693

Requires assessment that protection mechanisms are correctly implemented and producing intended security outcomes.

addresses: CWE-693

The POA&M process ensures identified weaknesses in protection mechanisms are documented and scheduled for remediation, reducing the duration they remain exploitable.

addresses: CWE-693

Ongoing control assessments and analysis of monitoring data enable timely detection and response when protection mechanisms fail.

addresses: CWE-693

Impact analysis identifies changes that could weaken or disable existing protection mechanisms.

NVD Description

Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

Deeper analysisAI

Automated synthesis unavailable for this CVE.

Details

CWE(s)

Affected Products

mozilla
firefox
≤ 140.11.0 · ≤ 151.0.0
mozilla
thunderbird
≤ 140.11 · ≤ 151.0.0

References