CVE-2026-8949

Integer overflow in the Widget: Win32 component

State: Published
Severity: 7.5 High
Published: May 19, 2026
Updated: May 19, 2026
Reserved: May 19, 2026

Description

Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	CISA-ADP

Weaknesses

CWE-190 Integer Overflow or Wraparound

Affected Products

Product	Versions
FirefoxMozilla	140.11 through 140.*Not affected 151 and laterNot affected
ThunderbirdMozilla	140.11 through 140.*Not affected 151 and laterNot affected

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1355639
https://www.mozilla.org/security/advisories/mfsa2026-46/
https://www.mozilla.org/security/advisories/mfsa2026-48/
https://www.mozilla.org/security/advisories/mfsa2026-50/
https://www.mozilla.org/security/advisories/mfsa2026-51/

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