CVE-2026-2778
Critical · CVSS 10.0Mozilla Firefox / Thunderbird — Sandbox escape via incorrect boundary conditions in DOM Core & HTML (CWE-119 buffer boundary violation)
- CVSS
- 10.0
- nvd
- EPSS
- —
- KEV
- No
- Class
- oss containerizable
- NVD-CWE-noinfo, CWE-119
Description
Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
Search profile — drives PoC discovery
Symbols DOM CoreDOM HTMLsandbox escapeboundary conditionsbugzilla 2016358mfsa2026-13mfsa2026-14mfsa2026-15mfsa2026-16
Keywords CVE-2026-2778Firefox sandbox escapeThunderbird sandbox escapeDOM boundary condition exploitFirefox 148 exploitFirefox ESR 115.33Firefox ESR 140.8Thunderbird 148Thunderbird 140.8mfsa2026-13 PoCCWE-119 Firefox DOMbugzilla 2016358 exploit
Versions: Firefox < 148; Firefox ESR < 115.33; Firefox ESR < 140.8; Thunderbird < 148; Thunderbird < 140.8
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2016358
- https://www.mozilla.org/security/advisories/mfsa2026-13/
- https://www.mozilla.org/security/advisories/mfsa2026-14/
- https://www.mozilla.org/security/advisories/mfsa2026-15/
- https://www.mozilla.org/security/advisories/mfsa2026-16/
- https://www.mozilla.org/security/advisories/mfsa2026-17/
- https://access.redhat.com/errata/RHSA-2026:3338
- https://access.redhat.com/errata/RHSA-2026:3339
- https://access.redhat.com/errata/RHSA-2026:3361
- https://access.redhat.com/errata/RHSA-2026:3491
- https://access.redhat.com/errata/RHSA-2026:3492
- https://access.redhat.com/errata/RHSA-2026:3493
Status: enriched · ingested 2026-06-30T06:00:22.000Z · profiled 2026-07-01T00:30:14.000Z