CVE-2021-4158

Severity: medium (CVSS 6.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2022-08-24 · updated 2026-06-17
Weakness: CWE-476

Description

A NULL pointer dereference issue was found in the ACPI code of QEMU. A malicious, privileged user within the guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition.

Affected products

QEMU: from 6.0.0 before 7.0.0 — fixed in 7.0.0
Red Hat Enterprise Linux: 9.0

How to fix

Upgrade to a fixed version: QEMU 7.0.0. Check the vendor advisory for mitigations.

References

https://access.redhat.com/security/cve/CVE-2021-4158
https://bugzilla.redhat.com/show_bug.cgi?id=2035002
https://gitlab.com/qemu-project/qemu/-/commit/9bd6565ccee68f72d5012e24646e12a1c662827e
https://gitlab.com/qemu-project/qemu/-/issues/770
https://www.mail-archive.com/qemu-devel%40nongnu.org/msg857944.html
https://access.redhat.com/security/cve/CVE-2021-4158
https://bugzilla.redhat.com/show_bug.cgi?id=2035002
https://gitlab.com/qemu-project/qemu/-/commit/9bd6565ccee68f72d5012e24646e12a1c662827e
https://gitlab.com/qemu-project/qemu/-/issues/770
https://www.mail-archive.com/qemu-devel%40nongnu.org/msg857944.html

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