Qemu-kvm: vnc websocket handshake use-after-free
Priority LOW 34CWE-416Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 15 fixed, 1 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00864 58th percentileScored 2026-11-07
Fix Partial qemu: 10.1.2Red Hat: 13 advisoriesRed Hat: 15 fixed, 1 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | qemu | 2.6.0 to before 10.1.2 | 10.1.2 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 10 | — | 18:10.0.0-14.el10_1.5 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 8 | — | 8100020251120003312.489197e6 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 8 | — | 8100020251202222937.489197e6 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | — | 8040020260916092751.522a0ee4 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | — | 8040020260916092751.522a0ee4 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | — | 8080020260910092120.63b34585 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | — | 8080020260910092120.63b34585 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 9 | — | 17:10.1.0-17.el9_8 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | — | 17:6.2.0-11.el9_0.10 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | — | 17:7.2.0-14.el9_2.24 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 9.4 Extended Update Support | — | 17:8.2.0-11.el9_4.18 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 9.4 Extended Update Support | — | 17:8.2.0-11.el9_4.19 | Patch available | CNA |
| Red Hat | Red Hat OpenShift Container Platform 4.12 | — | 412.86.202608241157-0 | Patch available | CNA |
| Red Hat | Red Hat OpenShift Container Platform 4.16 | — | 416.94.202601071926-0 | Patch available | CNA |
| Red Hat | Red Hat OpenShift Container Platform 4.17 | — | 417.94.202601120213-0 | Patch available | CNA |
| Red Hat | Red Hat OpenShift Container Platform 4.18 | — | 418.94.202601071817-0 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 6 | — | — | Not affected | CNA |
| Red Hat | Red Hat Enterprise Linux 7 | — | — | Not affected | CNA |
| Red Hat | Red Hat Enterprise Linux 7 | — | — | No fix listed | CNA |
- qemu Vendor— Affected 2.6.0 to before 10.1.2 Fixed in 10.1.2 Patch available CNA
- Red Hat Enterprise Linux 10 VendorRed Hat Affected — Fixed in 18:10.0.0-14.el10_1.5 Patch available CNA
- Red Hat Enterprise Linux 8 VendorRed Hat Affected — Fixed in 8100020251120003312.489197e6 Patch available CNA
- Red Hat Enterprise Linux 8 VendorRed Hat Affected — Fixed in 8100020251202222937.489197e6 Patch available CNA
- Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support VendorRed Hat Affected — Fixed in 8040020260916092751.522a0ee4 Patch available CNA
- Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On VendorRed Hat Affected — Fixed in 8040020260916092751.522a0ee4 Patch available CNA
- Red Hat Enterprise Linux 8.8 Telecommunications Update Service VendorRed Hat Affected — Fixed in 8080020260910092120.63b34585 Patch available CNA
- Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions VendorRed Hat Affected — Fixed in 8080020260910092120.63b34585 Patch available CNA
- Red Hat Enterprise Linux 9 VendorRed Hat Affected — Fixed in 17:10.1.0-17.el9_8 Patch available CNA
- Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions VendorRed Hat Affected — Fixed in 17:6.2.0-11.el9_0.10 Patch available CNA
- Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions VendorRed Hat Affected — Fixed in 17:7.2.0-14.el9_2.24 Patch available CNA
- Red Hat Enterprise Linux 9.4 Extended Update Support VendorRed Hat Affected — Fixed in 17:8.2.0-11.el9_4.18 Patch available CNA
- Red Hat Enterprise Linux 9.4 Extended Update Support VendorRed Hat Affected — Fixed in 17:8.2.0-11.el9_4.19 Patch available CNA
- Red Hat OpenShift Container Platform 4.12 VendorRed Hat Affected — Fixed in 412.86.202608241157-0 Patch available CNA
- Red Hat OpenShift Container Platform 4.16 VendorRed Hat Affected — Fixed in 416.94.202601071926-0 Patch available CNA
- Red Hat OpenShift Container Platform 4.17 VendorRed Hat Affected — Fixed in 417.94.202601120213-0 Patch available CNA
- Red Hat OpenShift Container Platform 4.18 VendorRed Hat Affected — Fixed in 418.94.202601071817-0 Patch available CNA
- Red Hat Enterprise Linux 6 VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat Enterprise Linux 7 VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat Enterprise Linux 7 VendorRed Hat Affected — Fixed in — No fix listed CNA
CPE names CNA · 17
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:/o:redhat:enterprise_linux:10.1 | 10.1 | — | Red Hat |
| cpe:/a:redhat:enterprise_linux:8::appstream | 8 | — | Red Hat |
| cpe:/a:redhat:enterprise_linux:8::crb | 8 | — | Red Hat |
| cpe:/a:redhat:rhel_aus:8.4::appstream | 8.4 | — | Red Hat |
| cpe:/a:redhat:rhel_eus_long_life:8.4::appstream | 8.4 | — | Red Hat |
| cpe:/a:redhat:rhel_e4s:8.8::appstream | 8.8 | — | Red Hat |
| cpe:/a:redhat:rhel_tus:8.8::appstream | 8.8 | — | Red Hat |
| cpe:/a:redhat:enterprise_linux:9::appstream | 9 | — | Red Hat |
| cpe:/a:redhat:rhel_e4s:9.0::appstream | 9.0 | — | Red Hat |
| cpe:/a:redhat:rhel_e4s:9.2::appstream | 9.2 | — | Red Hat |
- cpe:/o:redhat:enterprise_linux:10.1 Versions 10.1 — ·Red Hat
- cpe:/a:redhat:enterprise_linux:8::appstream Versions 8 — ·Red Hat
- cpe:/a:redhat:enterprise_linux:8::crb Versions 8 — ·Red Hat
- cpe:/a:redhat:rhel_aus:8.4::appstream Versions 8.4 — ·Red Hat
- cpe:/a:redhat:rhel_eus_long_life:8.4::appstream Versions 8.4 — ·Red Hat
- cpe:/a:redhat:rhel_e4s:8.8::appstream Versions 8.8 — ·Red Hat
- cpe:/a:redhat:rhel_tus:8.8::appstream Versions 8.8 — ·Red Hat
- cpe:/a:redhat:enterprise_linux:9::appstream Versions 9 — ·Red Hat
- cpe:/a:redhat:rhel_e4s:9.0::appstream Versions 9.0 — ·Red Hat
- cpe:/a:redhat:rhel_e4s:9.2::appstream Versions 9.2 — ·Red Hat
Show 7 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:/a:redhat:rhel_eus:9.4::appstream | 9.4 | — | Red Hat |
| cpe:/a:redhat:openshift:4.12::el8 | 4.12 | — | Red Hat |
| cpe:/a:redhat:openshift:4.16::el9 | 4.16 | — | Red Hat |
| cpe:/a:redhat:openshift:4.17::el9 | 4.17 | — | Red Hat |
| cpe:/a:redhat:openshift:4.18::el9 | 4.18 | — | Red Hat |
| cpe:/o:redhat:rhel_els:6 | 6 | — | Red Hat |
| cpe:/o:redhat:rhel_els:7 | 7 | — | Red Hat |
- cpe:/a:redhat:rhel_eus:9.4::appstream Versions 9.4 — ·Red Hat
- cpe:/a:redhat:openshift:4.12::el8 Versions 4.12 — ·Red Hat
- cpe:/a:redhat:openshift:4.16::el9 Versions 4.16 — ·Red Hat
- cpe:/a:redhat:openshift:4.17::el9 Versions 4.17 — ·Red Hat
- cpe:/a:redhat:openshift:4.18::el9 Versions 4.18 — ·Red Hat
- cpe:/o:redhat:rhel_els:6 Versions 6 — ·Red Hat
- cpe:/o:redhat:rhel_els:7 Versions 7 — ·Red Hat
Remediation
- Fix · CNA qemu Fixed in 10.1.2
Red Hat 13 advisories
- RHSA-2026:69131 Released 2026-09-21 · Red Hat rating Importantvirt:rhel security update
- Red Hat Enterprise Linux AppStream AUS (v.8.4) hivex-1.3.18-21.module+el8.4.0+10770+19c037f9.src::virt:rhel, hivex-1.3.18-21.module+el8.4.0+10770+19c037f9.x86_64::virt:rhel, hivex-devel-1.3.18-21.module+el8.4.0+10770+19c037f9.x86_64::virt:rhel +47
- Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) SLOF-20191022-3.git899d9883.module+el8.3.0+6423+e4cb6418.noarch::virt:rhel, SLOF-20191022-3.git899d9883.module+el8.3.0+6423+e4cb6418.src::virt:rhel, hivex-1.3.18-21.module+el8.4.0+10770+19c037f9.aarch64::virt:rhel +47
- RHSA-2026:68513 Released 2026-09-17 · Red Hat rating Importantvirt:rhel security update
- Red Hat Enterprise Linux AppStream E4S (v.8.8) SLOF-20210217-2.module+el8.8.0+20737+daad9f3b.noarch::virt:rhel, SLOF-20210217-2.module+el8.8.0+20737+daad9f3b.src::virt:rhel, hivex-1.3.18-23.module+el8.8.0+16781+9f4724c2.ppc64le::virt:rhel +47
- Red Hat Enterprise Linux AppStream TUS (v.8.8) hivex-1.3.18-23.module+el8.8.0+16781+9f4724c2.src::virt:rhel, hivex-1.3.18-23.module+el8.8.0+16781+9f4724c2.x86_64::virt:rhel, hivex-devel-1.3.18-23.module+el8.8.0+16781+9f4724c2.x86_64::virt:rhel +47
- RHSA-2026:59831 Released 2026-09-03 · Red Hat rating ImportantOpenShift Container Platform 4.12.97 bug fix and security update
- Red Hat OpenShift Container Platform 4.12 rhcos-x86_64-412.86.202608241157-0
Show 10 more Red Hat advisories
- RHSA-2026:22147 Released 2026-06-01 · Red Hat rating Lowqemu-kvm security update
- Red Hat Enterprise Linux AppStream E4S (v.9.0) qemu-guest-agent-17:6.2.0-11.el9_0.10, qemu-img-17:6.2.0-11.el9_0.10, qemu-kvm-17:6.2.0-11.el9_0.10 +19
- RHSA-2026:18772 Released 2026-05-19 · Red Hat rating Moderateqemu-kvm security update
- Red Hat Enterprise Linux AppStream (v. 9) qemu-guest-agent-17:10.1.0-17.el9_8, qemu-img-17:10.1.0-17.el9_8, qemu-kvm-17:10.1.0-17.el9_8 +17
- RHSA-2026:5578 Released 2026-03-24 · Red Hat rating Moderatevirt:rhel and virt-devel:rhel security update
- Red Hat Enterprise Linux AppStream (v. 8) SLOF-20210217-2.module+el8.10.0+20141+6faa2812.noarch::virt:rhel, SLOF-20210217-2.module+el8.10.0+20141+6faa2812.src::virt:rhel, hivex-1.3.18-23.module+el8.9.0+18724+20190c23.aarch64::virt:rhel +47
- Red Hat Enterprise Linux CRB (v. 8) SLOF-20210217-2.module+el8.10.0+20141+6faa2812.src::virt-devel:rhel, hivex-1.3.18-23.module+el8.9.0+18724+20190c23.i686::virt-devel:rhel, hivex-devel-1.3.18-23.module+el8.9.0+18724+20190c23.i686::virt-devel:rhel +47
- RHSA-2026:3165 Released 2026-02-24 · Red Hat rating Moderateqemu-kvm security update
- Red Hat Enterprise Linux AppStream EUS (v.9.4) qemu-guest-agent-17:8.2.0-11.el9_4.19, qemu-img-17:8.2.0-11.el9_4.19, qemu-kvm-17:8.2.0-11.el9_4.19 +17
- RHSA-2026:3077 Released 2026-02-23 · Red Hat rating Moderateqemu-kvm security update
- Red Hat Enterprise Linux AppStream E4S (v.9.2) qemu-guest-agent-17:7.2.0-14.el9_2.24, qemu-img-17:7.2.0-14.el9_2.24, qemu-kvm-17:7.2.0-14.el9_2.24 +16
- RHSA-2026:1831 Released 2026-02-05 · Red Hat rating Moderateqemu-kvm security update
- Red Hat Enterprise Linux AppStream (v. 10) qemu-guest-agent-18:10.0.0-14.el10_1.5, qemu-img-18:10.0.0-14.el10_1.5, qemu-kvm-18:10.0.0-14.el10_1.5 +17
- RHSA-2026:0702 Released 2026-01-22 · Red Hat rating ImportantOpenShift Container Platform 4.17.47 bug fix and security update
- Red Hat OpenShift Container Platform 4.17 rhcos-aarch64-417.94.202601120213-0, rhcos-ppc64le-417.94.202601120213-0, rhcos-s390x-417.94.202601120213-0 +1
- RHSA-2026:0332 Released 2026-01-15 · Red Hat rating ImportantOpenShift Container Platform 4.18.31 bug fix and security update
- Red Hat OpenShift Container Platform 4.18 rhcos-aarch64-418.94.202601071817-0, rhcos-ppc64le-418.94.202601071817-0, rhcos-s390x-418.94.202601071817-0 +1
- RHSA-2026:0326 Released 2026-01-15 · Red Hat rating ImportantOpenShift Container Platform 4.16.55 bug fix and security update
- Red Hat OpenShift Container Platform 4.16 rhcos-aarch64-416.94.202601071926-0, rhcos-ppc64le-416.94.202601071926-0, rhcos-s390x-416.94.202601071926-0 +1
- RHSA-2025:23228 Released 2025-12-17 · Red Hat rating Moderateqemu-kvm security update
- Red Hat Enterprise Linux AppStream EUS (v.9.4) qemu-guest-agent-17:8.2.0-11.el9_4.18, qemu-img-17:8.2.0-11.el9_4.18, qemu-kvm-17:8.2.0-11.el9_4.18 +17
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:1831 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2026:5578 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:18772 |
| Red Hat Enterprise Linux AppStream AUS (v.8.4) | Fixed | RHSA-2026:69131 |
| Red Hat Enterprise Linux AppStream E4S (v.8.8) | Fixed | RHSA-2026:68513 |
| Red Hat Enterprise Linux AppStream E4S (v.9.0) | Fixed | RHSA-2026:22147 |
| Red Hat Enterprise Linux AppStream E4S (v.9.2) | Fixed | RHSA-2026:3077 |
| Red Hat Enterprise Linux AppStream EUS (v.9.4) | Fixed | RHSA-2025:23228, RHSA-2026:3165 |
| Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) | Fixed | RHSA-2026:69131 |
| Red Hat Enterprise Linux AppStream TUS (v.8.8) | Fixed | RHSA-2026:68513 |
| Red Hat Enterprise Linux CRB (v. 8) | Fixed | RHSA-2026:5578 |
| Red Hat OpenShift Container Platform 4.12 | Fixed | RHSA-2026:59831 |
| Red Hat OpenShift Container Platform 4.16 | Fixed | RHSA-2026:0326 |
| Red Hat OpenShift Container Platform 4.17 | Fixed | RHSA-2026:0702 |
| Red Hat OpenShift Container Platform 4.18 | Fixed | RHSA-2026:0332 |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2025-11234
- 2026-10-03 Alias added: GHSA-hm8v-8c3v-cxfq
- 2026-10-10 Affected versions changed · Red Hat
- 2026-10-10 Fix available: openshift/[email protected], openshift/[email protected], openshift/[email protected] +1 · CNA
References
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Sources
- CVE-2025-11234 · CVE Program
- CVE-2025-11234 · NVD
- FIRST EPSS
- GHSA-hm8v-8c3v-cxfq · GitHub Advisory Database · CC BY 4.0
- CVE-2025-11234 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences