CVE-2026-121604

Name	CVE-2026-121604
Description	wlroots before 0.20.2 contains an out-of-bounds read vulnerability in read_surface_class() in xwayland/xwm.c that allows local X11 clients to leak compositor heap memory. Attackers can set a WM_CLASS property with a NUL-terminated instance but unterminated class, exposing over-read heap bytes as the window class or app_id over IPC.
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)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
wlroots (PTS)	bookworm	0.15.1-6	vulnerable
	trixie	0.18.2-3	vulnerable
	forky, sid	0.20.2-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
wlroots	source	(unstable)	0.20.2-1

Notes

https://gitlab.freedesktop.org/wlroots/wlroots/-/work_items/4092
https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/5374
Fixed by: https://gitlab.freedesktop.org/wlroots/wlroots/-/commit/4412992469540b1d578cb94a5cd4e6e5829812dc (0.20.2)