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Vulnerability · Published Nov 3, 2026 · Assigned by VulnCheck

CVE-2026-121604wlroots before 0.20.2 Out-of-Bounds Read via read_surface_class() in xwm.c

Low 3.3

In plain English

A low-severity out-of-bounds read in wlroots from wlroots. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)3.3Low
Exploit odds (30 days)0.1%top 98.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12wlrootsno fix listedDEBIAN-CVE-2026-121604
Debian:13wlrootsno fix listedDEBIAN-CVE-2026-121604
Debian:14wlroots0.20.2-1DEBIAN-CVE-2026-121604
Ubuntu:22.04:LTSwlrootsno fix listedUBUNTU-CVE-2026-121604
Ubuntu:24.04:LTSwlrootsno fix listedUBUNTU-CVE-2026-121604
Ubuntu:26.04:LTSwlrootsno fix listedUBUNTU-CVE-2026-121604
Ubuntu:26.10wlrootsno fix listedUBUNTU-CVE-2026-121604

Affected products (as reported)

VendorProductVersions
wlroots wlroots 0 – before 0.20.2

Weakness: CWE-125 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

References