CVE-2025-26601 Xorg: xwayland: use-after-free in syncinittrigger()

What is CVE-2025-26601?

CVE-2025-26601 is a high-severity use after free vulnerability in Redhat Enterprise Linux, published on 25 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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.

Weakness: CWE-416

Which versions are affected by CVE-2025-26601?

It affects 4 products.

Products include Redhat Enterprise Linux, Tigervnc Tigervnc, X.org X Server, X.org Xwayland.

How do I fix CVE-2025-26601?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2025-26601 being exploited?

There is no known exploitation of CVE-2025-26601 in the wild and no public exploit code.

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• CVE-2021-20325 Missing fixes for CVE-2021-40438 and CVE-2021-26691 in the versions of httpd, as shipped in Red Hat Enterprise Linux 8.5.0, causes a securit Critical 9.8
• CVE-2018-25011 Memory corruption in libwebp Critical 9.8
• CVE-2018-25014 Other in libwebp Critical 9.8
• CVE-2014-3585 Supply chain in redhat-upgrade-tool Critical 9.8

All Redhat Enterprise Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-57295, AZL-57411, AZL-57482, BELL-CVE-2025-26601, CLSA-2025-1743071343, DEBIAN-CVE-2025-26601 and 2 more.