CVE-2026-118370

Name	CVE-2026-118370
Description	libexpat through 2.9.0 contains a signed integer overflow vulnerability in storeAtts() in lib/xmlparse.c that allows attackers to trigger out-of-bounds writes via oversized attribute counts. Attackers can supply a multi-gigabyte document with a start tag carrying over 2^30 attributes to overflow attIndex and nPrefixes, crashing applications or corrupting heap memory.
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)
Debian Bugs	1152337

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
expat (PTS)	bookworm	2.5.0-1+deb12u2	vulnerable
	bookworm (security)	2.5.0-1+deb12u5	vulnerable
	trixie	2.8.3-1~deb13u1	vulnerable
	trixie (security)	2.9.0-1~deb13u1	vulnerable
	forky, sid	2.9.0-1	vulnerable

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
expat	source	(unstable)	(unfixed)			1152337

https://github.com/libexpat/libexpat/pull/1450