CVE-2021-4145

Severity: medium (CVSS 6.5 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: none known
Published: 2022-01-25 · updated 2026-06-17
Weakness: CWE-476

Description

A NULL pointer dereference issue was found in the block mirror layer of QEMU in versions prior to 6.2.0. The `self` pointer is dereferenced in mirror_wait_on_conflicts() without ensuring that it's not NULL. A malicious unprivileged user within the guest could use this flaw to crash the QEMU process on the host when writing data reaches the threshold of mirroring node.

Affected products

QEMU: 6.1.0, 6.1.0-rc0, 6.1.0-rc1, 6.1.0-rc2, 6.1.0-rc3, 6.1.0-rc4
Red Hat Enterprise Linux: 8.0

References

https://bugzilla.redhat.com/show_bug.cgi?id=2034602
https://gitlab.com/qemu-project/qemu/-/commit/66fed30c9cd11854fc878a4eceb507e915d7c9cd
https://security.gentoo.org/glsa/202208-27
https://security.netapp.com/advisory/ntap-20220311-0004/
https://bugzilla.redhat.com/show_bug.cgi?id=2034602
https://gitlab.com/qemu-project/qemu/-/commit/66fed30c9cd11854fc878a4eceb507e915d7c9cd
https://security.gentoo.org/glsa/202208-27
https://security.netapp.com/advisory/ntap-20220311-0004/

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