CVE-2026-100818

CRITICAL 9.6CVE-2026-100818 · Published 29/09/2026 · updated 05/10/2026

Package	Affected versions	Patched versions
firefox mozilla	`≥ 141.0, < 153.4.0≥ 154.0.0, < 157.0.0< 140.17.0`	`153.4.0157.0.0140.17.0`
thunderbird mozilla	`≥ 141.0, < 153.4.0≥ 154.0, < 157.0< 140.17.0`	`153.4.0157.0140.17.0`

Description

Sandbox escape due to use-after-free in the Widget: Gtk component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.

References

bugzilla.mozilla.org/show_bug.cgi · Permissions Required
mozilla.org/security/advisories/mfsa2026-100 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-101 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-102 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-103 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-97 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-99 · Vendor Advisory

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