CVE-2026-12330

Name	CVE-2026-12330
Description	Incorrect boundary conditions in the Internationalization component. This vulnerability was fixed in Firefox ESR 140.12, Firefox ESR 115.37, and Thunderbird 140.12.
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-4635-1, DLA-4636-1, DSA-6350-1, DSA-6351-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
firefox-esr (PTS)	bookworm	140.12.0esr-1~deb12u1	fixed
	bookworm (security)	140.15.0esr-1~deb12u1	fixed
	trixie	140.12.0esr-1~deb13u1	fixed
	trixie (security)	140.15.0esr-1~deb13u1	fixed
	forky	140.14.0esr-2	fixed
	sid	140.15.0esr-1	fixed
thunderbird (PTS)	bookworm	1:140.12.0esr-1~deb12u1	fixed
	bookworm (security)	1:140.15.0esr-1~deb12u1	fixed
	trixie	1:140.12.0esr-1~deb13u1	fixed
	trixie (security)	1:140.15.0esr-1~deb13u1	fixed
	forky	1:140.14.0esr-1	fixed
	sid	1:153.2.0esr-1	fixed

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

Package	Type	Release	Fixed Version	Origin
firefox-esr	source	bullseye	140.12.0esr-1~deb11u1	DLA-4635-1
firefox-esr	source	bookworm	140.12.0esr-1~deb12u1	DLA-4635-1
firefox-esr	source	trixie	140.12.0esr-1~deb13u1	DSA-6350-1
firefox-esr	source	(unstable)	140.12.0esr-1
thunderbird	source	bullseye	1:140.12.0esr-1~deb11u1	DLA-4636-1
thunderbird	source	bookworm	1:140.12.0esr-1~deb12u1	DLA-4636-1
thunderbird	source	trixie	1:140.12.0esr-1~deb13u1	DSA-6351-1
thunderbird	source	(unstable)	1:140.12.0esr-1

Notes

https://www.mozilla.org/en-US/security/advisories/mfsa2026-58/#CVE-2026-12330
https://www.mozilla.org/en-US/security/advisories/mfsa2026-61/#CVE-2026-12330