Is CVE-2021-20233 being actively exploited?

CVE-2021-20233 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2021-20233?

CVE-2021-20233 has a CVSS 3.1 base score of 8.2 (HIGH).

CVE-2021-20233

HIGH · CVSS 8.2EPSS 0.6%EU EUVD

A flaw was found in grub2 in versions prior to 2.06. Setparam_prefix() in the menu rendering code performs a length calculation on the assumption that expressing a quoted single quote will require 3 characters, while it actually requires 4 characters which allows an attacker to corrupt memory by one byte for each quote in the input. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Key facts

CVSS score: 8.2 (v3.1)
Severity: HIGH
CVSS vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Weakness (CWE): CWE-787
EPSS score: 0.6% (48th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2021-7672)
Published: March 3, 2021
NVD last modified: June 17, 2026
Status: Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2021-7672 in the EU Vulnerability Database. Last updated in EUVD on August 3, 2024.

View on the EU Vulnerability Database

Affected products

fedoraproject / fedora
fedoraproject / fedora
gnu / grub2
netapp / ontap select deploy administration utility
redhat / enterprise linux
redhat / enterprise linux
redhat / enterprise linux server aus
redhat / enterprise linux server aus
redhat / enterprise linux server aus
redhat / enterprise linux server aus
redhat / enterprise linux server aus
redhat / enterprise linux server aus
redhat / enterprise linux server eus
redhat / enterprise linux server eus
redhat / enterprise linux server eus
redhat / enterprise linux server tus
redhat / enterprise linux server tus
redhat / enterprise linux server tus
redhat / enterprise linux server tus
redhat / enterprise linux workstation

Certified products that may be affected

26 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.

Red Hat Enterprise Linux 8 NSS Cryptographic Module - Red Hat, Inc. - FIPS 140 5513 - active
Red Hat Enterprise Linux 8 Kernel Cryptographic API - Red Hat, LLC - FIPS 140 5461 - active
Red Hat Enterprise Linux 8 Kernel Cryptographic API - Red Hat, Inc. - FIPS 140 5089 - active
Red Hat Enterprise Linux 8 OpenSSL Cryptographic Module - Red Hat®, Inc. - FIPS 140 4642 - historical
Red Hat Enterprise Linux 8 NSS Cryptographic Module - Red Hat®, Inc. - FIPS 140 4458 - historical

See all 26 in the Security Certifications Explorer.

References

https://bugzilla.redhat.com/show_bug.cgi?id=1926263(Issue Tracking, Patch, Third Party Advisory)
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZWZ36QK4IKU6MWDWNOOWKPH3WXZBHT2R/
https://security.gentoo.org/glsa/202104-05(Third Party Advisory)
https://security.netapp.com/advisory/ntap-20220325-0001/(Third Party Advisory)

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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