CVE-2026-74941

Name	CVE-2026-74941
Description	Privilege escalation in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DLA-4750-1, DSA-6451-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
firefox (PTS)	sid	154.0-1	fixed
firefox-esr (PTS)	bullseye	115.14.0esr-1~deb11u1	vulnerable
	bullseye (security)	140.14.0esr-1~deb11u1	fixed
	bookworm	140.12.0esr-1~deb12u1	vulnerable
	bookworm (security)	140.14.0esr-1~deb12u1	fixed
	trixie	140.12.0esr-1~deb13u1	vulnerable
	trixie (security)	140.14.0esr-1~deb13u1	fixed
	forky	140.13.0esr-2	vulnerable
	sid	140.14.0esr-2	fixed
thunderbird (PTS)	bullseye	1:115.12.0-1~deb11u1	vulnerable
	bullseye (security)	1:140.13.0esr-2~deb11u1	vulnerable
	bookworm	1:140.12.0esr-1~deb12u1	vulnerable
	bookworm (security)	1:140.13.0esr-2~deb12u1	vulnerable
	trixie	1:140.12.0esr-1~deb13u1	vulnerable
	trixie (security)	1:140.13.0esr-2~deb13u1	vulnerable
	forky	1:140.13.0esr-2	vulnerable
	sid	1:140.14.0esr-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Origin
firefox	source	(unstable)	154.0-1
firefox-esr	source	bullseye	140.14.0esr-1~deb11u1	DLA-4750-1
firefox-esr	source	bookworm	140.14.0esr-1~deb12u1	DLA-4750-1
firefox-esr	source	trixie	140.14.0esr-1~deb13u1	DSA-6451-1
firefox-esr	source	(unstable)	140.14.0esr-2
thunderbird	source	(unstable)	1:140.14.0esr-1

Notes

https://www.mozilla.org/en-US/security/advisories/mfsa2026-74/#CVE-2026-74941
https://www.mozilla.org/en-US/security/advisories/mfsa2026-76/#CVE-2026-74941
https://www.mozilla.org/en-US/security/advisories/mfsa2026-79/#CVE-2026-74941