CVE-2025-11234

Qemu-kvm: vnc websocket handshake use-after-free

Published Oct 3, 2025 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
EUVD EUVD EUVD-2025-32237 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.
Ubuntu USN Ubuntu USN USN-8412-1 QEMU vulnerabilities
Ubuntu USN Ubuntu USN USN-8073-1 QEMU vulnerabilities
History
Type Values Removed Values Added
First Time appeared Redhat rhel Els
CPEs cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:rhel_els:6
cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel Els
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4
Type Values Removed Values Added
First Time appeared Redhat rhel Aus
Redhat rhel Eus Long Life
CPEs cpe:/a:redhat:rhel_aus:8.4::appstream
cpe:/a:redhat:rhel_eus_long_life:8.4::appstream
Vendors & Products Redhat rhel Aus
Redhat rhel Eus Long Life
References
Type Values Removed Values Added
First Time appeared Redhat rhel Tus
CPEs cpe:/a:redhat:rhel_e4s:8.8::appstream
cpe:/a:redhat:rhel_tus:8.8::appstream
Vendors & Products Redhat rhel Tus
References
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4
Type Values Removed Values Added
CPEs cpe:/a:redhat:rhel_e4s:9.0::appstream
References
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:9 cpe:/a:redhat:enterprise_linux:9::appstream
References
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:8 cpe:/a:redhat:enterprise_linux:8::appstream
cpe:/a:redhat:enterprise_linux:8::crb
References
Type Values Removed Values Added
First Time appeared Redhat rhel E4s
CPEs cpe:/a:redhat:rhel_e4s:9.2::appstream
Vendors & Products Redhat rhel E4s
References
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10 cpe:/o:redhat:enterprise_linux:10.1
References
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4.18::el9
References
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:4 cpe:/a:redhat:openshift:4.16::el9
References
Type Values Removed Values Added
First Time appeared Redhat rhel Eus
CPEs cpe:/a:redhat:rhel_eus:9.4::appstream
Vendors & Products Redhat rhel Eus
References
Type Values Removed Values Added
CPEs cpe:/a:redhat:advanced_virtualization:8::el8
Vendors & Products Redhat advanced Virtualization
Type Values Removed Values Added
CPEs cpe:/o:redhat:rhivos:1
Vendors & Products Redhat rhivos
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Qemu-kvm: vnc websocket handshake use-after-free
First Time appeared Redhat
Redhat advanced Virtualization
Redhat enterprise Linux
Redhat openshift
Redhat rhivos
Weaknesses CWE-416
CPEs cpe:/a:redhat:advanced_virtualization:8::el8
cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
cpe:/o:redhat:rhivos:1
Vendors & Products Redhat
Redhat advanced Virtualization
Redhat enterprise Linux
Redhat openshift
Redhat rhivos
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Nov 5, 2026, 2:47 PM
Reserved
Oct 1, 2025, 5:03 PM
Status
Deferred
Published
Oct 3, 2025, 11:15 AM
Modified
Nov 5, 2026, 3:17 PM
Severity
Moderate
Public date
Sep 30, 2025, 12:18 PM