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 flaw 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. Reported-by: Grant Millar | Cylo <rid> Upstream patch: https://lists.nongnu.org/archive/html/qemu-devel/2025-10/msg00786.html
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.4 Extended Update Support Via RHSA-2025:23228 https://access.redhat.com/errata/RHSA-2025:23228