VNC WebSocket handshake use-after-free
CVE: CVE-2025-11234
Component: qemu-kvm
CWE: CWE-416
Severity: Moderate
CVSS v3: 7.5/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Release date: 2025-09-30T12:18:00+00:00

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.

Statement: This CVE has been rated as Moderate because it only affects the WebSocket protocol for communication (the VNC raw TCP socket is not affected) and the use of QEMU's in-process WebSocket feature is fairly niche.

Remediation:
For OpenShift Container Platform 4.16 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.16/html/release_notes/

You may download the oc tool and use it to inspect release image metadata for x86_64, s390x, ppc64le, and aarch64 architectures. The image digests may be found at https://quay.io/repository/openshift-release-dev/ocp-release?tab=tags.

The sha values for the release are as follows:

      (For x86_64 architecture)
      The image digest is sha256:283a4968c61885c67fd17ea4d6920b665c98d53fa85fc897e067d3c4c131da3b

      (For s390x architecture)
      The image digest is sha256:5db06d746a26930aa3a8ec756f77cfcf76bcfb838327a5c71d3a0e6d920b85c6

      (For ppc64le architecture)
      The image digest is sha256:444378df90349f12c84ec1447dfb2afa40fd28e6596d8d9ab9a37b9013fc6a62

      (For aarch64 architecture)
      The image digest is sha256:c837b6a0325105e8f1487cdebf12d1b41eaa609a88f37baf986f5361ba66b08b

All OpenShift Container Platform 4.16 users are advised to upgrade to these updated packages and images when they are available in the appropriate release channel. To check for available updates, use the OpenShift CLI (oc) or web console. Instructions for upgrading a cluster are available at https://docs.redhat.com/en/documentation/openshift_container_platform/4.16/html-single/updating_clusters/index#updating-cluster-cli.
For OpenShift Container Platform 4.17 see the following documentation,
which will be updated shortly for this release, for important instructions
on how to upgrade your cluster and fully apply this asynchronous errata
update:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.17/html/release_notes/

You may download the oc tool and use it to inspect release image metadata
for x86_64, s390x, ppc64le, and aarch64 architectures. The image digests
may be found at
https://quay.io/repository/openshift-release-dev/ocp-release?tab=tags.

The sha values for the release are as follows:

      (For x86_64 architecture)
      The image digest is sha256:d49a4f1a4532e3822e8769a97d87f538f9101701d3997e6e883c8abff7b58a43

      (For s390x architecture)
      The image digest is sha256:baded7c05358eda3d7bc20efdc3d2b963ba80f1639c2c80b2c58bc216a1375d1

      (For ppc64le architecture)
      The image digest is sha256:4714f7f59793e8f77cc5a95eb918bd43f9a6ff31de1b35fb59b45a07f7a3f118

      (For aarch64 architecture)
      The image digest is sha256:73e2429c13a91ea4e5031c61f94c57884a7251ece3e1bbb338523e7bf8246903

All OpenShift Container Platform 4.17 users are advised to upgrade to these
updated packages and images when they are available in the appropriate
release channel. To check for available updates, use the OpenShift CLI (oc)
or web console. Instructions for upgrading a cluster are available at
https://docs.redhat.com/en/documentation/openshift_container_platform/4.17/html-single/updating_clusters/index#updating-cluster-cli.
For OpenShift Container Platform 4.18 see the following documentation,
which will be updated shortly for this release, for important instructions
on how to upgrade your cluster and fully apply this asynchronous errata
update:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.18/html/release_notes/

You may download the oc tool and use it to inspect release image metadata
for x86_64, s390x, ppc64le, and aarch64 architectures. The image digests
may be found at
https://quay.io/repository/openshift-release-dev/ocp-release?tab=tags.

The sha values for the release are as follows:

      (For x86_64 architecture)
      The image digest is sha256:64e8c4cbd3199beb1ebb8d6a208cb81fdfe62f4e52d7586033f534d35f981244

      (For s390x architecture)
      The image digest is sha256:5b964fa43873a20a66b95769bbcd6c31b028f505281fb045bb3c2ed6ca114e91

      (For ppc64le architecture)
      The image digest is sha256:2108325c5ee08249e1b0c0ad6a3daab197f5e2a1a83c8600d27c49ad0ff94307

      (For aarch64 architecture)
      The image digest is sha256:b465cef295a81eaf055c87a9af6d8ecdcc11cb1e898895d6df527eb155a7ff82

All OpenShift Container Platform 4.18 users are advised to upgrade to these
updated packages and images when they are available in the appropriate
release channel. To check for available updates, use the OpenShift CLI (oc)
or web console. Instructions for upgrading a cluster are available at
https://docs.redhat.com/en/documentation/openshift_container_platform/4.18/html-single/updating_clusters/index#updating-cluster-cli.