#VU104195 Access of uninitialized pointer in X.org Server and Xwayland - CVE-2025-26599

Vulnerability identifier: #VU104195

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-2025-26599

CWE-ID: CWE-824

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 usage of an uninitialized pointer within the compRedirectWindow() 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=2345253
https://gitlab.freedesktop.org/xorg/xserver/-/commit/c1ff84be
https://gitlab.freedesktop.org/xorg/xserver/-/commit/b07192a8
https://www.zerodayinitiative.com/advisories/ZDI-25-138/

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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.