CVE-2026-93834 Qemu-kvm: 9pfs: use-after-free race in tlcreate/twalk allows vm guest escape
A race condition in QEMU's 9pfs allows guest users to trigger a use-after-free, leading to VM escape and arbitrary host code execution.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-93834?
CVE-2026-93834 is a high-severity use after free vulnerability in Red Hat Enterprise Linux 10, published on 25 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
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.
Weakness: CWE-416
Which versions are affected by CVE-2026-93834?
How do I fix CVE-2026-93834?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-93834 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-93834 exists.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as AZL-105278, DEBIAN-CVE-2026-93834, ECHO-cb4a-4db7-9170, GHSA-86c2-8qp8-q2vh, OESA-2026-4584, OESA-2026-4585 and 3 more.