CVE-2025-26601
HIGHCVSS Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
3Description
A use-after-free flaw was found in X.Org and Xwayland. When changing an alarm, the values of the change mask are evaluated one after the other, changing the trigger values as requested, and eventually, SyncInitTrigger() is called. If one of the changes triggers an error, the function will return early, not adding the new sync object, possibly causing a use-after-free when the alarm eventually triggers.
Analysis
A use-after-free flaw was found in X.Org and Xwayland. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
Technical Context
This vulnerability is classified as Use After Free (CWE-416), which allows attackers to access freed memory to execute arbitrary code or crash the application. A use-after-free flaw was found in X.Org and Xwayland. When changing an alarm, the values of the change mask are evaluated one after the other, changing the trigger values as requested, and eventually, SyncInitTrigger() is called. If one of the changes triggers an error, the function will return early, not adding the new sync object, possibly causing a use-after-free when the alarm eventually triggers. Affected products include: Tigervnc, X.Org X Server, X.Org Xwayland, Redhat Enterprise Linux.
Affected Products
Tigervnc, X.Org X Server, X.Org Xwayland, Redhat Enterprise Linux.
Remediation
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Use smart pointers or garbage-collected languages. Set pointers to NULL after freeing. Enable memory sanitizers.
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External POC / Exploit Code
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