CVE-2026-100818criticalCWE-416

CVE-2026-100818: critical vulnerability in Mozilla Firefox

Sandbox escape due to use-after-free in the Widget: Gtk component

Published · Updated

28Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 9.6epss 0.3%
exploitation probability
0.3%top 84% of all CVEs
observed exploitation
nono source reports it
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Affected products
Mozilla · FirefoxMozilla · Thunderbird
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References
https://bugzilla.mozilla.org/show_bug.cgi?id=2069399https://www.mozilla.org/security/advisories/mfsa2026-100/https://www.mozilla.org/security/advisories/mfsa2026-101/https://www.mozilla.org/security/advisories/mfsa2026-102/https://www.mozilla.org/security/advisories/mfsa2026-103/https://www.mozilla.org/security/advisories/mfsa2026-97/https://www.mozilla.org/security/advisories/mfsa2026-99/