CVE-2025-11234: Use-After-Free (CVSS 7.5)

Description

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.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-416 Use After Free

References

Other References

https://access.redhat.com/errata/RHSA-2025:23228 https://access.redhat.com/errata/RHSA-2026:0326 https://access.redhat.com/errata/RHSA-2026:0332 https://access.redhat.com/errata/RHSA-2026:0702 https://access.redhat.com/errata/RHSA-2026:1831 https://access.redhat.com/errata/RHSA-2026:3077 https://access.redhat.com/errata/RHSA-2026:3165 https://access.redhat.com/errata/RHSA-2026:5578 https://access.redhat.com/security/cve/CVE-2025-11234 https://bugzilla.redhat.com/show_bug.cgi?id=2401209

Frequently Asked Questions

What is CVE-2025-11234? +

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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2025-11234? +

CVE-2025-11234 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

How do I check if I'm vulnerable to CVE-2025-11234? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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