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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.

PUBLISHED Reserved 2025-10-01 | Published 2025-10-03 | Updated 2026-06-01 | Assigner redhat




HIGH: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Problem types

Use After Free

Product status

Default status
unaffected

2.6.0 (semver) before 10.1.2
affected

Default status
affected

18:10.0.0-14.el10_1.5 (rpm) before *
unaffected

Default status
affected

8100020251120003312.489197e6 (rpm) before *
unaffected

Default status
affected

8100020251202222937.489197e6 (rpm) before *
unaffected

Default status
affected

17:10.1.0-17.el9_8 (rpm) before *
unaffected

Default status
affected

17:6.2.0-11.el9_0.10 (rpm) before *
unaffected

Default status
affected

17:7.2.0-14.el9_2.24 (rpm) before *
unaffected

Default status
affected

17:8.2.0-11.el9_4.18 (rpm) before *
unaffected

Default status
affected

17:8.2.0-11.el9_4.19 (rpm) before *
unaffected

Default status
affected

416.94.202601071926-0 (rpm) before *
unaffected

Default status
affected

417.94.202601120213-0 (rpm) before *
unaffected

Default status
affected

418.94.202601071817-0 (rpm) before *
unaffected

Default status
unaffected

Default status
unaffected

Default status
affected

Timeline

2025-09-30:Reported to Red Hat.
2025-09-30:Made public.

Credits

Red Hat would like to thank Grant Millar (Cylo) for reporting this issue.

References

access.redhat.com/errata/RHSA-2025:23228 (RHSA-2025:23228) vendor-advisory

access.redhat.com/errata/RHSA-2026:0326 (RHSA-2026:0326) vendor-advisory

access.redhat.com/errata/RHSA-2026:0332 (RHSA-2026:0332) vendor-advisory

access.redhat.com/errata/RHSA-2026:0702 (RHSA-2026:0702) vendor-advisory

access.redhat.com/errata/RHSA-2026:1831 (RHSA-2026:1831) vendor-advisory

access.redhat.com/errata/RHSA-2026:18772 (RHSA-2026:18772) vendor-advisory

access.redhat.com/errata/RHSA-2026:22147 (RHSA-2026:22147) vendor-advisory

access.redhat.com/errata/RHSA-2026:3077 (RHSA-2026:3077) vendor-advisory

access.redhat.com/errata/RHSA-2026:3165 (RHSA-2026:3165) vendor-advisory

access.redhat.com/errata/RHSA-2026:5578 (RHSA-2026:5578) vendor-advisory

access.redhat.com/security/cve/CVE-2025-11234 vdb-entry

bugzilla.redhat.com/show_bug.cgi?id=2401209 (RHBZ#2401209) issue-tracking

cve.org (CVE-2025-11234)

nvd.nist.gov (CVE-2025-11234)

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