CVE-2026-50260 Details
Description
A use-after-free flaw was found in the X.Org X server and Xwayland in FreeCounter(). A client that sets up multiple SyncCounters and awaits on those triggers can trigger a use-after-free when destroying those counters via a second client connection. This may be used to crash the server, or for privilege escalation if the X server runs as root.
A use-after-free vulnerability has been identified in the X.Org X server and Xwayland, affecting versions of the X server through 21.1.22 and Xwayland through 24.1.9. The issue arises in the 'FreeCounter()' function, where a client can set up multiple SyncCounters and await their triggers. When these counters are destroyed via a second client connection, it can lead to a use-after-free condition. This vulnerability could be exploited to crash the server or escalate privileges if the X server is running as root.
Users can upgrade to X.Org X server version 21.1.23 or Xwayland version 24.1.12, both of which include the necessary fix.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jun 9, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-416 | Use After Free | redhat-SADP |
| CWE-416 | Use After Free | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| x.org x server | < 21.1.23 |
CPE
Remediation
| |
| x.org xwayland | < 24.1.12 |
CPE
Remediation
| |
| redhat enterprise linux | 7.0 8.0 9.0 10.0 |
CPE
Remediation
| |
Change History
31 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Aug 5, 2026 | CVE Modified | redhat-SADP |
| Aug 5, 2026 | CVE Modified | [email protected] |
| Jul 27, 2026 | CVE Modified | redhat-SADP |
| Jul 27, 2026 | CVE Modified | [email protected] |
| Jul 27, 2026 | CVE Modified | [email protected] |
| Jul 27, 2026 | CVE Modified | [email protected] |
| Jul 27, 2026 | CVE Modified | [email protected] |
| Jul 15, 2026 | CVE Modified | redhat-SADP |
| Jul 13, 2026 | CVE Modified | redhat-SADP |
| Jul 13, 2026 | CVE Modified | [email protected] |
| Jul 13, 2026 | CVE Modified | [email protected] |
| Jul 9, 2026 | CVE Modified | redhat-SADP |
| Jul 9, 2026 | CVE Modified | [email protected] |
| Jul 8, 2026 | CVE Modified | [email protected] |
| Jul 8, 2026 | CVE Modified | redhat-SADP |
| Jul 8, 2026 | CVE Modified | [email protected] |
| Jul 7, 2026 | CVE Modified | [email protected] |
| Jul 7, 2026 | CVE Modified | redhat-SADP |
| Jul 7, 2026 | CVE Modified | [email protected] |
| Jun 30, 2026 | CVE Modified | redhat-SADP |
| Jun 25, 2026 | CVE Modified | [email protected] |
| Jun 24, 2026 | CVE Modified | [email protected] |
| Jun 22, 2026 | CVE Modified | [email protected] |
| Jun 18, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 11, 2026 | Initial Analysis | [email protected] |
| Jun 5, 2026 | New CVE Received | [email protected] |