{"cve":"CVE-2021-20181","nvd":{"published":"2021-05-13T16:15:07.653","modified":"2026-06-17T03:33:25.773","status":"Modified","description":"A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5.2.0. This flaw allows a malicious 9p client to cause a use-after-free error, potentially escalating their privileges on the system. The highest threat from this vulnerability is to confidentiality, integrity as well as system availability.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H","score":7.5},"cwes":["CWE-362","CWE-367"],"references":["https://bugzilla.redhat.com/show_bug.cgi?id=1927007","https://lists.debian.org/debian-lts-announce/2021/02/msg00024.html","https://lists.debian.org/debian-lts-announce/2022/09/msg00008.html","https://security.netapp.com/advisory/ntap-20210720-0009/","https://www.zerodayinitiative.com/advisories/ZDI-21-159/"],"products":["debian:debian_linux","qemu:qemu"],"source":"nvd","synced_at":"2026-10-19T21:18:09.669877188+00:00"},"epss":{"cve":"CVE-2021-20181","score":0.00333,"percentile":0.26523,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}