CVE-2021-4122

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-08-24 · updated 2026-10-14
Weakness: CWE-345

Description

It was found that a specially crafted LUKS header could trick cryptsetup into disabling encryption during the recovery of the device. An attacker with physical access to the medium, such as a flash disk, could use this flaw to force a user into permanently disabling the encryption layer of that medium.

Affected products

cryptsetup: before 2.3.7; from 2.4.0 before 2.4.3 — fixed in 2.3.7, 2.4.3

How to fix

Upgrade to a fixed version: cryptsetup 2.3.7, 2.4.3. Check the vendor advisory for mitigations.

References

https://access.redhat.com/security/cve/CVE-2021-4122
https://bugzilla.redhat.com/show_bug.cgi?id=2031859
https://bugzilla.redhat.com/show_bug.cgi?id=2032401
https://gitlab.com/cryptsetup/cryptsetup/-/commit/0113ac2d889c5322659ad0596d4cfc6da53e356c
https://mirrors.edge.kernel.org/pub/linux/utils/cryptsetup/v2.4/v2.4.3-ReleaseNotes
https://access.redhat.com/security/cve/CVE-2021-4122
https://bugzilla.redhat.com/show_bug.cgi?id=2031859
https://bugzilla.redhat.com/show_bug.cgi?id=2032401
https://gitlab.com/cryptsetup/cryptsetup/-/commit/0113ac2d889c5322659ad0596d4cfc6da53e356c
https://mirrors.edge.kernel.org/pub/linux/utils/cryptsetup/v2.4/v2.4.3-ReleaseNotes
https://cert-portal.siemens.com/productcert/html/ssa-398330.html

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