Answer in brief
CVE-2026-50261 records a High severity (CVSS 7.8) vulnerability in Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: use-after-free in syncchangecounter(). The current sources do not mark it as known exploited. Affected software not mapped in the current feed; confirm the named product and version against your inventory.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2026-50261 records a High severity (CVSS 7.8) vulnerability in Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: use-after-free in syncchangecounter(). The current sources do not mark it as known exploited. Affected software not mapped in the current feed; confirm the named product and version against your inventory.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. 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.
Affected software not mapped in the current feed; confirm the named product and version against your inventory.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:x.org:x_server:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:x.org:xwayland:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* | Not reported | Not reported |
Published upstream
Jun 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 22, 2026
A use-after-free flaw was found in the X.Org X server and Xwayland in SyncChangeCounter(). A client that sets up multiple SyncCounters can trigger a use-after-free when destroying those counters via a second client connection while changing those counters. This may be used to crash the server, or for privilege escalation if the X server runs as root.
Quoted source text, attributed separately from HOL analysis.
CVSS is 7.8. 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.
Affected software not mapped in the current feed; confirm the named product and version against your inventory.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:x.org:x_server:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:x.org:xwayland:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* | Not reported | Not reported |
Published upstream
Jun 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 22, 2026
A use-after-free flaw was found in the X.Org X server and Xwayland in SyncChangeCounter(). A client that sets up multiple SyncCounters can trigger a use-after-free when destroying those counters via a second client connection while changing those counters. This may be used to crash the server, or for privilege escalation if the X server runs as root.
Quoted source text, attributed separately from HOL analysis.