{"id":"CVE-2026-93834","title":"A use-after-free vulnerability was found in QEMU's 9pfs subsystem","summary":"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 cont…","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","cwe":["CWE-416"],"vendor":"Red Hat","product":"qemu-kvm","affected":["qemu-kvm (all versions)","qemu-kvm","qemu-kvm","qemu-kvm-ma","virt-devel:rhel/qemu-kvm (all versions)","virt:rhel/qemu-kvm (all versions)","qemu-kvm (all versions)","qemu-kvm","openshift/ose-rhel-coreos-8 (all versions)","openshift/ose-rhel-coreos-9 (all versions)","qemu-kvm-rhev"],"published":"2026-09-25","updated":"2026-09-29","sourceUpdated":"2026-09-29T21:29:07.663","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-93834","references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-93834","label":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2537939","label":"secalert@redhat.com"},{"url":"https://gitlab.com/qemu-project/qemu/-/work_items/4491","label":"secalert@redhat.com"},{"url":"https://gitlab.com/qemu-project/qemu/-/work_items/4491","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93834.json"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-93834"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-93834"}],"tags":["nvd","exploit-available","cve.org","csaf","vex","red-hat"],"epss":0.00405,"epssPercentile":0.34556,"exploits":{"github":1,"githubRepos":["https://github.com/suominen/CVE-2026-93834"],"checkedAt":"2026-10-27T19:23:28.798Z"},"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"total","timestamp":"2026-09-25T13:49:32.754375Z"},"ingestedAt":"2026-09-25T14:09:46.369Z","slug":"CVE-2026-93834","body":"## Overview\n\nA 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat Enterprise Linux for NVIDIA 26, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux for NVIDIA 26, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-09-25 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93834.json)","depth":"midnight","depthScore":60,"depthScoreParts":{"impact":48.4,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[]}