CVE-2026-50261
Use-After-Free in X.Org X Server and Xwayland
Publication date: 2026-06-05
Last updated on: 2026-06-05
Assigner: Red Hat, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| xorg | x11_server | to 21.1.22 (inc) |
| xorg | x11_server_xwayland | to 24.1.9 (inc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-416 | The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2026-50261 is a use-after-free vulnerability found in the X.Org X server and Xwayland, specifically in the SyncChangeCounter() function.
This flaw occurs when a client sets up multiple SyncCounters and then destroys those counters via a second client connection while changing them, which can trigger the use-after-free condition.
Exploiting this vulnerability allows any connected X client to potentially crash the server or escalate privileges if the X server is running with root privileges.
How can this vulnerability impact me? :
This vulnerability can impact you by allowing an attacker with access to the X server to cause a denial of service through a server crash.
More seriously, if the X server is running with root privileges, an attacker could exploit this flaw to escalate their privileges, potentially gaining unauthorized root access.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, you should update the affected Xorg components to fixed versions.
- Upgrade xorg-x11-server to version 21.1.23 or later.
- Upgrade xorg-x11-server-Xwayland to version 24.1.12 or later.
These updates address the use-after-free flaw in the SyncChangeCounter() function and prevent exploitation that could lead to crashes or privilege escalation.