{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-93834","assignerOrgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","state":"PUBLISHED","assignerShortName":"redhat","dateReserved":"2026-09-18T18:12:23.908Z","datePublished":"2026-09-25T13:36:17.597Z","dateUpdated":"2026-10-31T07:56:30.823Z"},"containers":{"cna":{"title":"Qemu-kvm: 9pfs: use-after-free race in tlcreate/twalk allows vm guest escape","metrics":[{"other":{"content":{"value":"Important","namespace":"https://access.redhat.com/security/updates/classification/"},"type":"Red Hat severity rating"}},{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"LOCAL","availabilityImpact":"HIGH","baseScore":8.8,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","version":"3.1"},"format":"CVSS"}],"descriptions":[{"lang":"en","value":"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":[{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"qemu-kvm","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:10"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 6","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"qemu-kvm","defaultStatus":"unaffected","cpes":["cpe:/o:redhat:enterprise_linux:6"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"qemu-kvm","defaultStatus":"unaffected","cpes":["cpe:/o:redhat:enterprise_linux:7"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"qemu-kvm-ma","defaultStatus":"unaffected","cpes":["cpe:/o:redhat:enterprise_linux:7"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"virt-devel:rhel/qemu-kvm","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"virt:rhel/qemu-kvm","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"qemu-kvm","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:9"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux for NVIDIA 26","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"qemu-kvm","defaultStatus":"unknown","cpes":["cpe:/a:redhat:enterprise_linux_nvidia:"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"openshift/ose-rhel-coreos-8","defaultStatus":"affected","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"openshift/ose-rhel-coreos-9","defaultStatus":"affected","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 5","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"openshift/ose-rhel-coreos-9","defaultStatus":"affected","cpes":["cpe:/a:redhat:openshift:5"]},{"vendor":"Red Hat","product":"Red Hat OpenStack Platform 13 (Queens)","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"qemu-kvm-rhev","defaultStatus":"unaffected","cpes":["cpe:/a:redhat:openstack:13"]}],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-93834","tags":["vdb-entry","x_refsource_REDHAT"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2537939","name":"RHBZ#2537939","tags":["issue-tracking","x_refsource_REDHAT"]},{"url":"https://gitlab.com/qemu-project/qemu/-/work_items/4491"}],"datePublic":"2026-09-22T00:00:00.000Z","problemTypes":[{"descriptions":[{"cweId":"CWE-416","description":"Use After Free","lang":"en","type":"CWE"}]}],"x_redhatCweChain":"CWE-416: Use After Free","workarounds":[{"lang":"en","value":"Do not configure 9pfs/VirtFS filesystem sharing (-fsdev, -virtfs) on affected QEMU instances. If host-guest file sharing is required, use virtio-fs (virtiofsd) as an alternative, which does not use the vulnerable 9pfs code path."}],"timeline":[{"lang":"en","time":"2026-09-22T00:00:00.000Z","value":"Reported to Red Hat."},{"lang":"en","time":"2026-09-22T00:00:00.000Z","value":"Made public."}],"providerMetadata":{"orgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","shortName":"redhat","dateUpdated":"2026-10-31T07:56:30.823Z"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"references":[{"url":"https://gitlab.com/qemu-project/qemu/-/work_items/4491","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-25T13:49:32.754375Z","id":"CVE-2026-93834","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-25T13:50:26.440Z"}}]}}