Use-after-Free in X.Org/Xwayland SyncInitTrigger
CVE-2025-26601 Published on February 25, 2025

Xorg: xwayland: use-after-free in syncinittrigger()
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.

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Vulnerability Analysis

CVE-2025-26601 can be exploited with local system access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.

Attack Vector:
LOCAL
Attack Complexity:
LOW
Privileges Required:
LOW
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
HIGH

Timeline

Reported to Red Hat.

Made public. 13 days later.

Weakness Type

What is a Dangling pointer Vulnerability?

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

CVE-2025-26601 has been classified to as a Dangling pointer vulnerability or weakness.


Products Associated with CVE-2025-26601

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2025-26601 are published in these products:

Tigervnc
 
Xorg X Server
 
Xorg Xwayland
 
Red Hat Enterprise Linux (RHEL)
 
Red Hat Rhel Els
 
Red Hat Rhel Aus
 
Red Hat Rhel Tus
 
Red Hat Rhel E4s
 
Red Hat Rhel Eus
 

Exploit Probability

EPSS
0.05%
Percentile
16.24%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.