CVE-2026-100831

HIGH 8.8CVE-2026-100831 · Published 29/09/2026 · updated 13/10/2026

Package	Affected versions	Patched versions
firefox mozilla	`≥ 154.0.0, < 157.0.0< 153.4.0`	`157.0.0153.4.0`
thunderbird mozilla	`≥ 154.0, < 157.0< 153.4.0`	`157.0153.4.0`

Description

Use-after-free in the DOM: UI Events & Focus Handling component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.

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/mfsa2026-103 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-97 · Vendor Advisory

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