CVE-2026-12294
Published: 16 June 2026
Summary
CVE-2026-12294 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 28.3th 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-2026-37085
Vulnerability details
Sandbox escape in the DOM: Workers component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Explicit sandbox escape in browser DOM/Workers directly enables Escape to Host.
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.
Designation of a manager and policy dissemination ensures privileges are assigned according to defined roles.
Regular reviews catch incorrect privilege assignments to users, roles, or processes.
Explicitly specifying privileges and group/role memberships for accounts reduces the risk of incorrect privilege assignments.
Implements a reliable, tamperproof protection mechanism whose completeness can be assured.
The control requires explicit definition of separated access authorizations, making incorrect privilege assignments that bundle conflicting duties harder to implement.
Ensures privileges are assigned only as necessary rather than incorrectly over-granted.
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.