CVE-2021-20233: High severity GNU GRUB2 vulnerability
A flaw was found in grub2 in versions prior to 2.06. Setparamprefix() 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.
Other sources
A flaw was found in grub2 in versions prior to 2.06. Setparamprefix() 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.
— MITRE
There's a flaw on grub2 menu rendering code setparamprefix() 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. This allow an attacker to corrupt memory by one byte for each quote in the input.
— Red Hat
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is CVE-2021-20233?
CVE-2021-20233 is a vulnerability found in grub2 versions prior to 2.06.
What is the severity of CVE-2021-20233?
The severity of CVE-2021-20233 is high with a severity value of 8.2.
Which software is affected by CVE-2021-20233?
The following software is affected by CVE-2021-20233: grub2 versions prior to 2.06, Gnu Grub2, Redhat Enterprise Linux, and other related distributions.
How can an attacker exploit CVE-2021-20233?
An attacker can exploit CVE-2021-20233 by corrupting memory through a length calculation error in the menu rendering code of grub2.
Where can I find more information about CVE-2021-20233?
You can find more information about CVE-2021-20233 on the following references: [1](https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1927436), [2](https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1934252), [3](https://access.redhat.com/errata/RHSA-2021:0698).