QEMU QIOChannelWebsock UAF via WebSocket handshake
CVE-2025-11234 Published on October 3, 2025
Qemu-kvm: vnc websocket handshake use-after-free
A flaw was found in QEMU. If the QIOChannelWebsock object is freed while it is waiting to complete a handshake, a GSource is leaked. This can lead to the callback firing later on and triggering a use-after-free in the use of the channel. This can be abused by a malicious client with network access to the VNC WebSocket port to cause a denial of service during the WebSocket handshake prior to the VNC client authentication.
Vulnerability Analysis
CVE-2025-11234 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Timeline
Reported to Red Hat.
Made public.
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-2025-11234 has been classified to as a Dangling pointer vulnerability or weakness.
Products Associated with CVE-2025-11234
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Exploit Probability
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.