CVE-2026-121604

medium

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.

References

https://www.vulncheck.com/advisories/wlroots-before-0.20.2-out-of-bounds-read-via-read-surface-class-in-xwm-c

https://gitlab.freedesktop.org/wlroots/wlroots/-/work_items/4092

https://gitlab.freedesktop.org/wlroots/wlroots/-/releases/0.20.2

https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/5374

https://gitlab.freedesktop.org/wlroots/wlroots/-/commit/851cdd0089004884bd85a95ad21f04009cb5a53a

https://gitlab.freedesktop.org/wlroots/wlroots/-/commit/4412992469540b1d578cb94a5cd4e6e5829812dc

https://gitlab.freedesktop.org/wlroots/wlroots/-/blob/0.20.1/xwayland/xwm.c#L661-L678

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-116039

Details

Source: Mitre, NVD

Published: 2026-11-03

Updated: 2026-11-07

Risk Information

CVSS v2

Base Score: 1.7

Vector: CVSS2#AV:L/AC:L/Au:S/C:P/I:N/A:N

Severity: Low

CVSS v3

Base Score: 3.3

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Severity: Low

CVSS v4

Base Score: 4.8

Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Severity: Medium

EPSS

EPSS: 0.00111