CVE-2026-84122

Use-after-free in the Audio/Video component

State: Published
Severity: 5.4 Medium
Published: Sep 1, 2026
Updated: Sep 1, 2026
Reserved: Sep 1, 2026

Description

Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

Scores

CVSS	Score	Vector	Source
3.1	5.4 Medium	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N	CISA-ADP

Weaknesses

CWE-416 Use After Free

Affected Products

Product	Versions
FirefoxMozilla	140.15 through 140.Not affected 153.2 through 153.Not affected 155 and laterNot affected
ThunderbirdMozilla	140.15 through 140.Not affected 153.2 through 153.Not affected 155 and laterNot affected

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2059965
https://www.mozilla.org/security/advisories/mfsa2026-82/
https://www.mozilla.org/security/advisories/mfsa2026-84/
https://www.mozilla.org/security/advisories/mfsa2026-85/
https://www.mozilla.org/security/advisories/mfsa2026-86/
https://www.mozilla.org/security/advisories/mfsa2026-87/
https://www.mozilla.org/security/advisories/mfsa2026-88/

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