CVE-2026-12296
Published: 16 June 2026
Summary
CVE-2026-12296 is a critical-severity Protection Mechanism Failure (CWE-693) vulnerability in Mozilla Firefox. Its CVSS base score is 9.6 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Escape to Host (T1611); ranked at the 31.2th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-37087
Vulnerability details
Sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Direct sandbox escape in process sandboxing enables Escape to Host (T1611).
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
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.
Implements a reliable, tamperproof protection mechanism whose completeness can be assured.
Procedures for training on protection mechanisms reduce the chance of protection mechanism failures being present or exploitable.
Documented procedures to implement assessment, authorization, and monitoring controls prevent these protection mechanisms from failing due to undefined processes.
Direct evaluation of whether controls produce desired security outcomes detects protection mechanism failures and enables remediation.
Requires assessment that protection mechanisms are correctly implemented and producing intended security outcomes.
The POA&M process ensures identified weaknesses in protection mechanisms are documented and scheduled for remediation, reducing the duration they remain exploitable.
Ongoing control assessments and analysis of monitoring data enable timely detection and response when protection mechanisms fail.
Impact analysis identifies changes that could weaken or disable existing protection mechanisms.