Race Condition Affecting qemu package, versions <1:5.2+dfsg-4


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.32% (24th percentile)

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  • Snyk IDSNYK-ECHOLATEST-QEMU-18321996
  • published27 Jul 2026
  • disclosed13 May 2021

Introduced: 13 May 2021

CVE-2021-20181  (opens in a new tab)
CWE-362  (opens in a new tab)

How to fix?

Upgrade Echo:latest qemu to version 1:5.2+dfsg-4 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream qemu package and not the qemu package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

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 Base Scores

version 3.1