CVE-2025-11234Use After Free in Qemu

Severity
7.5HIGHNVD
OSV5.5
EPSS
0.1%
top 66.81%
CISA KEV
Not in KEV
Exploit
No known exploits
Timeline
PublishedOct 3
Latest updateMar 4

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.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitability: 3.9 | Impact: 3.6

Affected Packages16 packages

debiandebian/qemu< qemu 1:7.2+dfsg-7+deb12u18 (bookworm)
Debianqemu/qemu< 1:7.2+dfsg-7+deb12u18+2
Ubuntuqemu/qemu< 1:6.2+dfsg-2ubuntu6.28+2

🔴Vulnerability Details

3
OSV
qemu vulnerabilities2026-03-04
GHSA
GHSA-hm8v-8c3v-cxfq: A flaw was found in QEMU2025-10-03
OSV
CVE-2025-11234: A flaw was found in QEMU2025-10-03

📋Vendor Advisories

5
Ubuntu
QEMU vulnerabilities2026-03-04
Microsoft
Qemu-kvm: vnc websocket handshake use-after-free2025-10-14
Red Hat
qemu-kvm: VNC WebSocket handshake use-after-free2025-09-30
Debian
CVE-2025-11234: qemu - A flaw was found in QEMU. If the QIOChannelWebsock object is freed while it is w...2025
Microsoft
Configuring a proxy in a stream context might allow for CRLF injection in URIs2024-11-12

🕵️Threat Intelligence

1
Bleepingcomputer
Microsoft October 2025 Patch Tuesday fixes 6 zero-days, 172 flaws2025-10-14