CVE-2026-93834
Qemu-kvm: 9pfs: use-after-free race in tlcreate/twalk allows vm guest escape
At a glance
- Severity
- HIGH 8.8
- EPSS
- EPSS 0.40 % · percentile 35 (2026-10-28)
- State
- PUBLISHED
- Published
- Updated
- Assigner
- redhat
- NVD status
- Awaiting Analysis
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.
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 8.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H | redhat |
| CVSS 3.1 | HIGH 8.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H | NVD · secalert@redhat.com (Primary) |
Weaknesses (CWE)
European references
- ENISA EUVD · EUVD-2026-87092
- GCVE · GCVE-0-2026-93834
Affected products
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
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |