CVE-2025-14321

CRITICAL 9.8CVE-2025-14321 · Published 09/12/2025 · updated 07/10/2026

In short

CVE-2025-14321 is a CRITICAL (CVSS 9.8) vulnerability affecting firefox (mozilla), thunderbird (mozilla).
Chance of exploitation in the next 30 days (EPSS): 0.60%, higher than 48.5% of all vulnerabilities.
Fix: update to 140.6.0, 146.0 or later.

Package	Affected versions	Patched versions
firefox mozilla	`< 140.6.0< 146.0`	`140.6.0146.0`
thunderbird mozilla	`< 140.6.0< 146.0`	`140.6.0146.0`

Description

Use-after-free in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 146, Firefox ESR 140.6, Thunderbird 146, and Thunderbird 140.6.

References

bugzilla.mozilla.org/show_bug.cgi · Issue Tracking
mozilla.org/security/advisories/mfsa2025-92 · Vendor Advisory
mozilla.org/security/advisories/mfsa2025-94 · Vendor Advisory
mozilla.org/security/advisories/mfsa2025-95 · Vendor Advisory
mozilla.org/security/advisories/mfsa2025-96 · Vendor Advisory

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Package

Affected versions

Patched versions

firefox

mozilla

< 140.6.0< 146.0

140.6.0146.0

thunderbird

mozilla

< 140.6.0< 146.0

140.6.0146.0

More vulnerabilities in firefox

See all →