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CVE-2021-4158: QEMU can crash if a guest user runs a specially crafted ACPI command

CVE-2021-4158 · published 4 years ago

Summary

A flaw in QEMU's ACPI code can be exploited by a malicious guest user to crash the QEMU process on the host, causing the host to become unresponsive. This can happen when a guest user with elevated privileges runs a carefully crafted command. To protect your host, update to the latest version of QEMU.

What to do

Update qemu qemu to version 7.0.0 or later.

Affected software

Vendor	Product	Affected versions
qemu	qemu	>= 6.0.0, < 7.0.0 `cpe:2.3:a:qemu:qemu::::::::`
redhat	enterprise_linux	9.0 `cpe:2.3:o:redhat:enterprise_linux:9.0:::::::*`

Original advisory text

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 o...

References

https://access.redhat.com/security/cve/CVE-2021-4158 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2035002 Issue Tracking Patch Third Party Advisory
https://gitlab.com/qemu-project/qemu/-/commit/9bd6565ccee68f72d5012e24646e12a1c6... Patch Third Party Advisory
https://gitlab.com/qemu-project/qemu/-/issues/770 Exploit Third Party Advisory
https://www.mail-archive.com/qemu-devel%40nongnu.org/msg857944.html Patch Third Party Advisory

Fix within

Internet-facing 60 days

Internal At next upgrade

Not known to be exploited
Needs hands-on effort to exploit (estimated)
Gives an attacker partial control (estimated)

Severity

6.0 Medium

Exploitation

<1% chance of attack within 30 days

Type

CWE-476NULL Pointer Dereference

Timeline

Published24 Aug 2022

Updated4 Nov 2026

First seen11 Apr 2026

Sources

CVE-2021-4158 · OSV

CVE-2021-4158 · NVD

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