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Fencer Vulns
medium 4.3

CVE-2021-4122 json

It was found that a specially crafted LUKS header could trick cryptsetup into disabling encryption during the recovery of the device.

published 2022-08-24 4 y ago modified 2026-10-14 26 d ago also EUVD-2021-33997

cvss
4.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 25%
public exploits
0
none known

Summary

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.

Patch / fix

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.5
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • cryptsetup Debian 14, Debian 13, Debian 12 2:2.4.3-1

debian advisories DEBIAN-CVE-2021-4122

  • cryptsetup Ubuntu 20.04 LTS 2:2.2.2-3ubuntu2.4
  • cryptsetup Ubuntu 22.04 LTS 2:2.4.3-1ubuntu1

ubuntu advisories UBUNTU-CVE-2021-4122

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • cryptsetup RHEL 8 2.3.3-4.el8_5.1
  • veritysetup RHEL 8 2.3.3-4.el8_5.1
  • integritysetup RHEL 8 2.3.3-4.el8_5.1
  • cryptsetup-libs RHEL 8 2.3.3-4.el8_5.1
  • cryptsetup-reencrypt RHEL 8 2.3.3-4.el8_5.1

red hat advisories RHSA-2022:0370

  • cryptsetup SLE Module for Basesystem 15 SP3, SLE Micro 5.1 2.3.7-150300.3.5.1

suse advisories SUSE-SU-2022:0144-1

  • cryptsetup openSUSE Tumbleweed 2.4.3-1.1
  • cryptsetup openSUSE Leap 15.3 2.3.7-150300.3.5.1
  • varnish Package Hub 15 SP4, openSUSE Leap 15.4 7.1.0-bp154.2.3.1

opensuse advisories openSUSE-SU-2024:11754-1openSUSE-SU-2022:0144-1

  • cryptsetup Rocky Linux 8 2.3.3-4.el8_5.1

rocky linux advisories RLSA-2022:0370

  • cryptsetup Alpine 3.14, Alpine 3.13, Alpine 3.12 2.3.7-r0
  • cryptsetup Alpine 3.24, Alpine 3.23, Alpine 3.22 +7 more 2.4.3-r0

alpine advisories ALPINE-CVE-2021-4122

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-4122 updated cvss 5.9

cryptsetup: disable encryption via header rewrite

  • Red Hat Enterprise Linux AppStream (v. 8) cryptsetup-devel 2.3.3-4.el8_5.1, cryptsetup-debuginfo 2.3.3-4.el8_5.1, veritysetup-debuginfo 2.3.3-4.el8_5.1, cryptsetup-debugsource 2.3.3-4.el8_5.1, integritysetup-debuginfo 2.3.3-4.el8_5.1, cryptsetup-libs-debuginfo 2.3.3-4.el8_5.1, +1 more Red Hat Enterprise Linux BaseOS (v. 8) cryptsetup 2.3.3-4.el8_5.1, veritysetup 2.3.3-4.el8_5.1, integritysetup 2.3.3-4.el8_5.1, cryptsetup-libs 2.3.3-4.el8_5.1, cryptsetup-reencrypt 2.3.3-4.el8_5.1
    fixed: vendor fix RHSA-2022:0370
  • Red Hat Enterprise Linux 7 cryptsetup, veritysetup, cryptsetup-libs, cryptsetup-python, cryptsetup-reencrypt Red Hat Enterprise Linux 9 cryptsetup, veritysetup, integritysetup, cryptsetup-libs
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-23-348-10 updated cvss 4.3

Siemens SIMATIC S7-1500

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.0, < 3.1.5
    affected: fixed in V3.1.5, mitigation support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

Exploit prediction

0.32% chance of exploitation in the next 30 days, higher than 25% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 4.3 CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Affected products

  • n/a cryptsetup
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness
  • CWE-345 Insufficient Verification of Data Authenticity

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.