CVE-2026-4701

CRITICAL 9.8CVE-2026-4701 · Published 24/03/2026 · updated 17/06/2026

Package	Affected versions	Patched versions
firefox mozilla	`< 140.9.0< 149.0`	`140.9.0149.0`

Description

Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

References

bugzilla.mozilla.org/show_bug.cgi · Permissions Required
mozilla.org/security/advisories/mfsa2026-20 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-22 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-23
mozilla.org/security/advisories/mfsa2026-24

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