CVE-2026-2786

Use-after-free in the JavaScript Engine component

State: Published
Severity: 8.8 High
Published: Feb 24, 2026
Updated: May 10, 2026
Reserved: Feb 19, 2026

Description

Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Scores

CVSS	Score	Vector	Source
3.1	8.8 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H	CISA-ADP

Weaknesses

CWE-416 Use After Free

Affected Products

Product	Versions
FirefoxMozilla	140.8 through 140.*Not affected 148 and laterNot affected
ThunderbirdMozilla	140.8 through 140.*Not affected 148 and laterNot affected

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2013612
https://www.mozilla.org/security/advisories/mfsa2026-13/
https://www.mozilla.org/security/advisories/mfsa2026-15/
https://www.mozilla.org/security/advisories/mfsa2026-16/
https://www.mozilla.org/security/advisories/mfsa2026-17/

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