wlroots before 0.20.2 contains an out-of-bounds read vulnerability in read_surface_class() in xwayland/xwm.c that
Affects wlrootsSource GCVE Database
Not known to be exploited · CVSS 4.8 Medium : upgrade to 0.20.2 when convenient.
Data as of 3 Nov 2026, 19:33 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 4.8 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 3.3 |
- Affects
- wlroots before 0.20.2
- Patch
- Available – fixed in 0.20.2
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 3 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 3 Nov 2026.
What to do
Upgrade wlroots/wlroots to 0.20.2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
GitHubwlroots/wlrootspkg:github/wlroots/wlrootsOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available in wlroots version 0.20.2 and later. Users should upgrade to version 0.20.2 or newer to remediate this vulnerability. No additional mitigation steps are indicated.
Description
An out-of-bounds read vulnerability exists in wlroots versions before 0.20.2 in the read_surface_class() function within xwayland/xwm.c. This flaw allows local X11 clients to leak compositor heap memory by setting a WM_CLASS property with a NUL-terminated instance but an unterminated class, causing an over-read of heap bytes exposed as the window class or app_id over IPC.
References
- nvd.nist.gov/vuln/detail/CVE-2026-121604 (opens in a new tab)
- gitlab.freedesktop.org/wlroots/wlroots/-/blob/0.20.1/xwayland/xwm.c (opens in a new tab)
- gitlab.freedesktop.org/wlroots/wlroots/-/commit/4412992469540b1d578cb94a5cd4e6e5829812dc (opens in a new tab)
- gitlab.freedesktop.org/wlroots/wlroots/-/commit/851cdd0089004884bd85a95ad21f04009cb5a53a (opens in a new tab)
- gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/5374 (opens in a new tab)
- gitlab.freedesktop.org/wlroots/wlroots/-/releases/0.20.2 (opens in a new tab)
- gitlab.freedesktop.org/wlroots/wlroots/-/work_items/4092 (opens in a new tab)
- vulncheck.com/advisories/wlroots-before-0.20.2-out-of-bounds-read-via-read-surface-class-in-xwm-c (opens in a new tab)