CVE-2026-2791

CRITICAL 9.8CVE-2026-2791 · Published 24/02/2026 · updated 17/06/2026

Package	Affected versions	Patched versions
firefox mozilla	`< 140.8.0< 148.0`	`140.8.0148.0`
thunderbird mozilla	`< 140.8.0< 148.0`	`140.8.0148.0`

Description

Mitigation bypass in the Networking: Cache component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

References

bugzilla.mozilla.org/show_bug.cgi · Issue Tracking
mozilla.org/security/advisories/mfsa2026-13 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-15 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-16 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-17 · Vendor Advisory

Running one of these products? Scan your site to see whether it exposes a vulnerable version.

Scan my site free