CVE-2021-20233: Fedoraproject Fedora

High severity, CVSS 8.2. EPSS: 0.6% chance of exploitation in the next 30 days.

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.

Affected products

• Fedoraproject Fedora: version 33 only; version 34 only
• GNU GRUB2: before 2.06 (fixed in 2.06)
• Netapp Ontap Select Deploy Administration Utility: affected versions not specified
• Red Hat Enterprise Linux: version 7.0 only; version 8.0 only
• Red Hat Enterprise Linux Server Aus: version 7.2 only; version 7.3 only; version 7.4 only; version 7.6 only; version 7.7 only; version 8.2 only
• Red Hat Enterprise Linux Server Eus: version 7.6 only; version 7.7 only; version 8.1 only
• Red Hat Enterprise Linux Server Tus: version 7.4 only; version 7.6 only; version 7.7 only; version 8.2 only
• Red Hat Enterprise Linux Workstation: version 7.0 only

Published 2021-03-03. Last modified 2026-06-17.