# CVE-2025-11234: Qemu-kvm: vnc websocket handshake use-after-free

Status: published. Published: 2025-10-03. Updated: 2026-11-05.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

-  /  (qemu): ≥ 2.6.0; < 10.1.2 (affected, semver). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10 (qemu-kvm): ≥ 18:10.0.0-14.el10_1.5; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (virt-devel:rhel): ≥ 8100020251120003312.489197e6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (virt:rhel): ≥ 8100020251202222937.489197e6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (virt:rhel): ≥ 8040020260916092751.522a0ee4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On (virt:rhel): ≥ 8040020260916092751.522a0ee4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Telecommunications Update Service (virt:rhel): ≥ 8080020260910092120.63b34585; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (virt:rhel): ≥ 8080020260910092120.63b34585; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (qemu-kvm): ≥ 17:10.1.0-17.el9_8; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions (qemu-kvm): ≥ 17:6.2.0-11.el9_0.10; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions (qemu-kvm): ≥ 17:7.2.0-14.el9_2.24; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.4 Extended Update Support (qemu-kvm): ≥ 17:8.2.0-11.el9_4.18; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.4 Extended Update Support (qemu-kvm): ≥ 17:8.2.0-11.el9_4.19; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4.12 (openshift/ose-rhel-coreos-8): ≥ 412.86.202608241157-0; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4.16 (openshift/ose-rhel-coreos-9): ≥ 416.94.202601071926-0; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4.17 (openshift/ose-rhel-coreos-9): ≥ 417.94.202601120213-0; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4.18 (openshift/ose-rhel-coreos-9): ≥ 418.94.202601071817-0; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (qemu-kvm): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (qemu-kvm): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (qemu-kvm-ma): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 0.86% as of 2026-11-05; percentile 58.78%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-416

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/errata/RHSA-2025:23228 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:0326 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:0332 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:0702 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:1831 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:18772 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:22147 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:3077 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:3165 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:5578 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:59831 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:68513 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:69131 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2025-11234 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2401209 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2025-11234; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2025-11234; retrieved 2026-11-05; source updated Not reported

Revision: ae082b600a0bad45e21d5f5dafa710106a3fa806111e79b009ef4e2fd8745431

Canonical: https://y2.dev/cve/CVE-2025-11234

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