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Fencer Vulns
high 7.5

CVE-2025-11234 json

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

published 2025-10-03 13 mo ago modified 2026-11-05 3 d ago also EUVD-2025-32560

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

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.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 10 18:10.0.0-14.el10_1.5
  • Red Hat Red Hat Enterprise Linux 8 8100020251120003312.489197e6, 8100020251202222937.489197e6
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 8040020260916092751.522a0ee4
  • Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On 8040020260916092751.522a0ee4
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service 8080020260910092120.63b34585
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 8080020260910092120.63b34585
  • Red Hat Red Hat Enterprise Linux 9 17:10.1.0-17.el9_8
  • Red Hat Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions 17:6.2.0-11.el9_0.10
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 17:7.2.0-14.el9_2.24
  • Red Hat Red Hat Enterprise Linux 9.4 Extended Update Support 17:8.2.0-11.el9_4.18, 17:8.2.0-11.el9_4.19
  • Red Hat Red Hat OpenShift Container Platform 4.12 412.86.202608241157-0
  • Red Hat Red Hat OpenShift Container Platform 4.16 416.94.202601071926-0
  • Red Hat Red Hat OpenShift Container Platform 4.17 417.94.202601120213-0
  • Red Hat Red Hat OpenShift Container Platform 4.18 418.94.202601071817-0
  • qemu Debian 12 1:7.2+dfsg-7+deb12u18
  • qemu Debian 13 1:10.0.7+ds-0+deb13u1
  • qemu Debian 14 1:10.1.3+ds-1

debian advisories DEBIAN-CVE-2025-11234

  • qemu Ubuntu 22.04 LTS 1:6.2+dfsg-2ubuntu6.28
  • qemu Ubuntu 24.04 LTS 1:8.2.2+ds-0ubuntu1.13
  • qemu Ubuntu 25.10 1:10.1.0+ds-5ubuntu2.4
  • qemu Ubuntu Pro 18.04 LTS 1:2.11+dfsg-1ubuntu7.42+esm5
  • qemu Ubuntu Pro 20.04 LTS 1:4.2-3ubuntu6.30+esm1

ubuntu advisories UBUNTU-CVE-2025-11234

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • qemu-kvm RHEL 9 17:10.1.0-17.el9_8
  • qemu-img RHEL 9 17:10.1.0-17.el9_8
  • qemu-kvm-core RHEL 9 17:10.1.0-17.el9_8
  • qemu-kvm-tools RHEL 9 17:10.1.0-17.el9_8
  • qemu-pr-helper RHEL 9 17:10.1.0-17.el9_8
  • qemu-kvm-common RHEL 9 17:10.1.0-17.el9_8
  • qemu-guest-agent RHEL 9 17:10.1.0-17.el9_8
  • qemu-kvm-audio-pa RHEL 9 17:10.1.0-17.el9_8

red hat advisories RHSA-2026:69131RHSA-2026:68513RHSA-2026:22147RHSA-2026:18772RHSA-2026:5578RHSA-2026:3165

  • qemu SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +3 more 6.2.0-150400.37.49.1
  • qemu SLE Micro 5.2 5.2.0-150300.142.1
  • qemu SLE Module for Server Applications 15 SP7, SLE Module for Package Hub 15 SP7, SLE Module for Basesystem 15 SP7 9.2.4-150700.3.11.1
  • qemu-linux-user SLE Module for Package Hub 15 SP7 9.2.4-150700.3.11.1
  • qemu Linux Micro 6.0 8.2.10-1.1
  • qemu SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Module for Server Applications 15 SP7 +3 more 7.1.0-150500.49.36.2
  • qemu SLES for SAP 15 SP6, SLES 15 SP6-LTSS, openSUSE Leap 15.6 8.2.10-150600.3.43.1
  • qemu-linux-user openSUSE Leap 15.6 8.2.10-150600.3.43.1

suse advisories SUSE-SU-2026:2406-1SUSE-SU-2026:0436-1SUSE-SU-2026:0356-1SUSE-SU-2026:0288-1SUSE-SU-2026:20038-1SUSE-SU-2026:0039-1

  • qemu openSUSE Leap 16.0 10.0.7-160000.1.1
  • qemu-linux-user openSUSE Leap 16.0 10.0.7-160000.1.1
  • qemu openSUSE Tumbleweed 10.1.3-1.1

opensuse advisories openSUSE-SU-2025:20171-1openSUSE-SU-2025:15821-1

  • qemu-kvm AlmaLinux 9 17:10.1.0-17.el9_8.alma.1
  • qemu-img AlmaLinux 9 17:10.1.0-17.el9_8.alma.1
  • qemu-kvm-core AlmaLinux 9 17:10.1.0-17.el9_8.alma.1
  • qemu-kvm-tools AlmaLinux 9 17:10.1.0-17.el9_8.alma.1
  • qemu-pr-helper AlmaLinux 9 17:10.1.0-17.el9_8.alma.1
  • qemu-kvm-common AlmaLinux 9 17:10.1.0-17.el9_8.alma.1
  • qemu-guest-agent AlmaLinux 9 17:10.1.0-17.el9_8.alma.1
  • qemu-kvm-audio-pa AlmaLinux 9 17:10.1.0-17.el9_8.alma.1

almalinux advisories ALSA-2026:18772ALSA-2026:5578ALSA-2026:1831

  • qemu-kvm Rocky Linux 9 7:10.1.0-17.el9_8
  • hivex Rocky Linux 8 1.3.18-23.module+el8.10.0+1835+43f01cbb
  • hivex Rocky Linux 8 1.3.18-23.module+el8.10.0+1590+a67ab969
  • netcf Rocky Linux 8 0.2.8-12.module+el8.10.0+1590+a67ab969
  • netcf Rocky Linux 8 0.2.8-12.module+el8.10.0+1835+43f01cbb
  • swtpm Rocky Linux 8 0.7.0-4.20211109gitb79fd91.module+el8.10.0+1835+43f01cbb
  • swtpm Rocky Linux 8 0.7.0-4.20211109gitb79fd91.module+el8.10.0+1590+a67ab969
  • libnbd Rocky Linux 8 1.6.0-6.module+el8.10.0+1870+0a714c9f

rocky linux advisories RLSA-2026:18772RLSA-2026:5578RLSA-2026:1831

  • qemu Azure Linux 3.0 8.2.0-23
  • qemu CBL-Mariner 2.0 6.2.0-25

azure linux advisories AZL-68193AZL-68202

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-11234 updated cvss 7.5

qemu-kvm: VNC WebSocket handshake use-after-free

  • Red Hat Enterprise Linux 7 qemu-img-ma, qemu-kvm-ma, qemu-kvm-tools-ma, qemu-kvm-common-ma
    affected: no fix available
  • Red Hat Enterprise Linux AppStream (v. 8) netcf 0.2.8-12.module+el8.9.0+18724+20190c23, hivex 1.3.18-23.module+el8.9.0+18724+20190c23, libnbd 1.6.0-6.module+el8.10.0+22250+3c790083, nbdkit 1.24.0-5.module+el8.9.0+18724+20190c23, nbdfuse 1.6.0-6.module+el8.10.0+22250+3c790083, seabios 1.16.0-4.module+el8.9.0+19570+14a90618, +104 more
    fixed: vendor fix RHSA-2026:5578
  • Red Hat Enterprise Linux AppStream (v. 9) qemu-img 10.1.0-17.el9_8, qemu-kvm 10.1.0-17.el9_8, qemu-kvm-core 10.1.0-17.el9_8, qemu-kvm-tools 10.1.0-17.el9_8, qemu-pr-helper 10.1.0-17.el9_8, qemu-kvm-common 10.1.0-17.el9_8, +13 more
    fixed: vendor fix RHSA-2026:18772
  • Red Hat Enterprise Linux AppStream (v. 10) qemu-img 10.0.0-14.el10_1.5, qemu-kvm 10.0.0-14.el10_1.5, qemu-kvm-core 10.0.0-14.el10_1.5, qemu-kvm-tools 10.0.0-14.el10_1.5, qemu-pr-helper 10.0.0-14.el10_1.5, qemu-kvm-common 10.0.0-14.el10_1.5, +13 more
    fixed: vendor fix RHSA-2026:1831
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) libnbd 1.2.2-1.module+el8.3.0+7353+9de0a3cc, netcf 0.2.8-12.module+el8.1.0+4066+0f1aadab, nbdfuse 1.2.2-1.module+el8.3.0+7353+9de0a3cc, nbdkit 1.16.2-4.module+el8.3.0+6922+fd575af8, hivex 1.3.18-21.module+el8.4.0+10770+19c037f9, seabios 1.13.0-2.module+el8.3.0+7353+9de0a3cc, +87 more
    fixed: vendor fix RHSA-2026:69131
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) libnbd 1.6.0-5.module+el8.8.0+16781+9f4724c2, netcf 0.2.8-12.module+el8.8.0+16781+9f4724c2, hivex 1.3.18-23.module+el8.8.0+16781+9f4724c2, nbdfuse 1.6.0-5.module+el8.8.0+16781+9f4724c2, nbdkit 1.24.0-5.module+el8.8.0+17308+05924798, SLOF 20210217-2.module+el8.8.0+20737+daad9f3b, +104 more
    fixed: vendor fix RHSA-2026:68513
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) qemu-img 6.2.0-11.el9_0.10, qemu-kvm 6.2.0-11.el9_0.10, qemu-kvm-core 6.2.0-11.el9_0.10, qemu-kvm-tools 6.2.0-11.el9_0.10, qemu-pr-helper 6.2.0-11.el9_0.10, qemu-kvm-common 6.2.0-11.el9_0.10, +15 more
    fixed: vendor fix RHSA-2026:22147
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) qemu-img 7.2.0-14.el9_2.24, qemu-kvm 7.2.0-14.el9_2.24, qemu-kvm-core 7.2.0-14.el9_2.24, qemu-kvm-tools 7.2.0-14.el9_2.24, qemu-pr-helper 7.2.0-14.el9_2.24, qemu-kvm-common 7.2.0-14.el9_2.24, +12 more
    fixed: vendor fix RHSA-2026:3077
show 9 more
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) qemu-img 8.2.0-11.el9_4.18, qemu-img 8.2.0-11.el9_4.19, qemu-kvm 8.2.0-11.el9_4.18, qemu-kvm 8.2.0-11.el9_4.19, qemu-kvm-core 8.2.0-11.el9_4.18, qemu-kvm-core 8.2.0-11.el9_4.19, +32 more
    fixed: vendor fix RHSA-2025:23228
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) libnbd 1.2.2-1.module+el8.3.0+7353+9de0a3cc, netcf 0.2.8-12.module+el8.1.0+4066+0f1aadab, nbdfuse 1.2.2-1.module+el8.3.0+7353+9de0a3cc, nbdkit 1.16.2-4.module+el8.3.0+6922+fd575af8, hivex 1.3.18-21.module+el8.4.0+10770+19c037f9, seabios 1.13.0-2.module+el8.3.0+7353+9de0a3cc, +88 more
    fixed: vendor fix RHSA-2026:69131
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) libnbd 1.6.0-5.module+el8.8.0+16781+9f4724c2, netcf 0.2.8-12.module+el8.8.0+16781+9f4724c2, hivex 1.3.18-23.module+el8.8.0+16781+9f4724c2, nbdfuse 1.6.0-5.module+el8.8.0+16781+9f4724c2, nbdkit 1.24.0-5.module+el8.8.0+17308+05924798, seabios 1.16.0-4.module+el8.8.0+19627+2d14cb21, +103 more
    fixed: vendor fix RHSA-2026:68513
  • Red Hat Enterprise Linux CRB (v. 8) netcf 0.2.8-12.module+el8.9.0+18724+20190c23, hivex 1.3.18-23.module+el8.9.0+18724+20190c23, libnbd 1.6.0-6.module+el8.10.0+22250+3c790083, nbdfuse 1.6.0-6.module+el8.10.0+22250+3c790083, seabios 1.16.0-4.module+el8.9.0+19570+14a90618, SLOF 20210217-2.module+el8.10.0+20141+6faa2812, +38 more
    fixed: vendor fix RHSA-2026:5578
  • Red Hat OpenShift Container Platform 4.12 rhcos 412.86.202608241157
    fixed: vendor fix RHSA-2026:59831
  • Red Hat OpenShift Container Platform 4.16 rhcos 416.94.202601071926
    fixed: vendor fix RHSA-2026:0326
  • Red Hat OpenShift Container Platform 4.17 rhcos 417.94.202601120213
    fixed: vendor fix RHSA-2026:0702
  • Red Hat OpenShift Container Platform 4.18 rhcos 418.94.202601071817
    fixed: vendor fix RHSA-2026:0332
  • Red Hat Enterprise Linux 6 qemu-img, qemu-kvm, qemu-kvm-tools, qemu-guest-agent, qemu-guest-agent-win32 Red Hat Enterprise Linux 7 qemu-img, qemu-kvm, libcacard, qemu-kvm-tools, libcacard-tools, qemu-kvm-common, +1 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
13 mo ago

Exploit prediction

0.86% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.4 Extended Update Support
  • Red Hat Red Hat OpenShift Container Platform 4.12
  • Red Hat Red Hat OpenShift Container Platform 4.16
  • Red Hat Red Hat OpenShift Container Platform 4.17
  • Red Hat Red Hat OpenShift Container Platform 4.18
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.