What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-25 · updated 2026-10-31
• Weakness: CWE-416

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 products

• Red Hat OpenShift Container Platform 4.18: all versions
• Red Hat Enterprise Linux 10: all versions
• Red Hat Enterprise Linux 8: all versions
• Red Hat Enterprise Linux 9: all versions
• Red Hat OpenShift Container Platform 5: all versions

References

• https://access.redhat.com/security/cve/CVE-2026-93834
• https://bugzilla.redhat.com/show_bug.cgi?id=2537939
• https://gitlab.com/qemu-project/qemu/-/work_items/4491
• https://gitlab.com/qemu-project/qemu/-/work_items/4491

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