Answer in brief
CVE-2026-121604 records a Medium severity (CVSS 4.8) vulnerability in wlroots before 0.20.2 Out-of-Bounds Read via read_surface_class() in xwm.c. The current sources do not mark it as known exploited. The current feed maps wlroots/wlroots (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 4.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps wlroots/wlroots (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| wlroots/wlrootsgeneric | >=0 <0.20.2 | 0.20.2 |
Published upstream
Nov 3, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 3, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 3, 2026
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.
Quoted source text, attributed separately from HOL analysis.