CVE-2025-11234
Qemu-kvm: vnc websocket handshake use-after-free
CVSS Score
7.5
EPSS Score
0.1%
EPSS Percentile
33th
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.
| CWE | CWE-416 |
| Published | Oct 3, 2025 |
| Last Updated | Mar 24, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
Red Hat / Red Hat Enterprise Linux 10
All versions affected Red Hat / Red Hat Enterprise Linux 8
All versions affected Red Hat / Red Hat Enterprise Linux 8
All versions affected Red Hat / Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
All versions affected Red Hat / Red Hat Enterprise Linux 9.4 Extended Update Support
All versions affected Red Hat / Red Hat Enterprise Linux 9.4 Extended Update Support
All versions affected Red Hat / Red Hat OpenShift Container Platform 4.16
All versions affected Red Hat / Red Hat OpenShift Container Platform 4.17
All versions affected Red Hat / Red Hat OpenShift Container Platform 4.18
All versions affected Red Hat / Red Hat Enterprise Linux 6
All versions affected Red Hat / Red Hat Enterprise Linux 7
All versions affected Red Hat / Red Hat Enterprise Linux 7
All versions affected Red Hat / Red Hat Enterprise Linux 9
All versions affected References
access.redhat.com: https://access.redhat.com/errata/RHSA-2025:23228 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:0326 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:0332 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:0702 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:1831 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:3077 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:3165 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:5578 access.redhat.com: https://access.redhat.com/security/cve/CVE-2025-11234 bugzilla.redhat.com: https://bugzilla.redhat.com/show_bug.cgi?id=2401209
Credits
Red Hat would like to thank Grant Millar (Cylo) for reporting this issue.