CVE-2021-20203

Severity: low (CVSS 3.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-02-25 · updated 2026-06-17
Weakness: CWE-190

Description

An integer overflow issue was found in the vmxnet3 NIC emulator of the QEMU for versions up to v5.2.0. It may occur if a guest was to supply invalid values for rx/tx queue size or other NIC parameters. A privileged guest user may use this flaw to crash the QEMU process on the host resulting in DoS scenario.

Affected products

Debian Linux: 9.0, 10.0
Fedoraproject Fedora: 33
QEMU: through 5.2.0

References

https://bugs.launchpad.net/qemu/+bug/1913873
https://bugzilla.redhat.com/show_bug.cgi?id=1922441
https://lists.debian.org/debian-lts-announce/2021/04/msg00009.html
https://lists.debian.org/debian-lts-announce/2022/09/msg00008.html
https://security.gentoo.org/glsa/202208-27
https://bugs.launchpad.net/qemu/+bug/1913873
https://bugzilla.redhat.com/show_bug.cgi?id=1922441
https://lists.debian.org/debian-lts-announce/2021/04/msg00009.html
https://lists.debian.org/debian-lts-announce/2022/09/msg00008.html
https://security.gentoo.org/glsa/202208-27

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