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Vulnerability · Published Sep 25, 2026 · Assigned by redhat

CVE-2026-93834Qemu-kvm: 9pfs: use-after-free race in tlcreate/twalk allows vm guest escape

High 8.8

In plain English

A high-severity use-after-free in Red Hat Enterprise Linux 10 from Red Hat. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.4%top 65.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack tooling1Public PoC

Official description

A use-after-free vulnerability was found in QEMU's 9pfs subsystem. A race condition between the main thread and a worker thread when processing concurrent Tlcreate and Twalk requests allows a malicious guest user to craft a fid path containing stale heap data, bypassing directory traversal restrictions and escaping the shared directory boundary. This can lead to arbitrary host file read/write and code execution (VM escape) as the QEMU process user.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12qemuno fix listedDEBIAN-CVE-2026-93834
Debian:13qemuno fix listedDEBIAN-CVE-2026-93834
Debian:14qemu1:11.1.2+ds-1DEBIAN-CVE-2026-93834
Ubuntu:22.04:LTSqemuno fix listedUBUNTU-CVE-2026-93834
Ubuntu:24.04:LTSqemuno fix listedUBUNTU-CVE-2026-93834
Ubuntu:26.04:LTSqemuno fix listedUBUNTU-CVE-2026-93834
Ubuntu:26.10qemuno fix listedUBUNTU-CVE-2026-93834
Ubuntu:26.04:LTSqemu-hweno fix listedUBUNTU-CVE-2026-93834
Ubuntu:26.10qemu-hweno fix listedUBUNTU-CVE-2026-93834

Affected products (as reported)

VendorProductVersions
Red Hat Red Hat Enterprise Linux 10 see references
Red Hat Red Hat Enterprise Linux 6 see references
Red Hat Red Hat Enterprise Linux 7 see references
Red Hat Red Hat Enterprise Linux 7 see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 9 see references
Red Hat Red Hat Enterprise Linux for NVIDIA 26 see references
Red Hat Red Hat OpenShift Container Platform 4 see references
Red Hat Red Hat OpenShift Container Platform 4 see references
Red Hat Red Hat OpenShift Container Platform 5 see references
Red Hat Red Hat OpenStack Platform 13 (Queens) see references

Weakness: CWE-416 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

References