#VU104197 Use-after-free in X.org Server and Xwayland - CVE-2025-26601

Vulnerability identifier: #VU104197

Vulnerability risk: Low

CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2025-26601

CWE-ID: CWE-416

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
X.org Server
Server applications / Other server solutions
Xwayland
Client/Desktop applications / Multimedia software

Vendor: X.org

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a use-after-free error within the SyncInitTrigger() function. A local user can execute arbitrary code with elevated privileges.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

X.org Server: 21.0.99.1 - 21.1.15

Xwayland: 21.0.99.901 - 24.1.5

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External links
https://bugzilla.redhat.com/show_bug.cgi?id=2345251
https://gitlab.freedesktop.org/xorg/xserver/-/commit/16a1242d
https://gitlab.freedesktop.org/xorg/xserver/-/commit/f52cea2f
https://gitlab.freedesktop.org/xorg/xserver/-/commit/8cbc90c8
https://gitlab.freedesktop.org/xorg/xserver/-/commit/c2857989
https://www.zerodayinitiative.com/advisories/ZDI-25-136/

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.