CVE-2026-12294
Critical · CVSS 9.6Mozilla Firefox / Thunderbird — Sandbox escape via DOM Workers
- CVSS
- 9.6
- nvd
- EPSS
- 0.36%
- 29th pct
- KEV
- No
- Class
- other
- CWE-693, CWE-266
Description
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.
Search profile — drives PoC discovery
Symbols DOMWorkerssandbox escapemfsa2026-57mfsa2026-58mfsa2026-59mfsa2026-60bug 2039873
Keywords CVE-2026-12294Firefox sandbox escapeDOM Workers sandboxFirefox 152 sandboxFirefox ESR 140.12Firefox ESR 115.37Thunderbird 152 sandboxmfsa2026-57CWE-693 Firefoxbugzilla 2039873
Versions: Firefox < 152, Firefox ESR < 140.12, Firefox ESR < 115.37, Thunderbird < 152, Thunderbird < 140.12
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2039873
- https://www.mozilla.org/security/advisories/mfsa2026-57/
- https://www.mozilla.org/security/advisories/mfsa2026-58/
- https://www.mozilla.org/security/advisories/mfsa2026-59/
- https://www.mozilla.org/security/advisories/mfsa2026-60/
- https://www.mozilla.org/security/advisories/mfsa2026-61/
- https://access.redhat.com/errata/RHSA-2026:27717
- https://access.redhat.com/errata/RHSA-2026:27733
- https://access.redhat.com/errata/RHSA-2026:27734
- https://access.redhat.com/errata/RHSA-2026:29940
- https://access.redhat.com/errata/RHSA-2026:30846
- https://access.redhat.com/errata/RHSA-2026:33445
Status: enriched · ingested 2026-06-19T00:00:04.000Z · profiled 2026-06-19T00:30:04.000Z