CVE-2021-20233 Memory corruption in grub2
An attacker can corrupt memory in GRUB2 via crafted input, potentially leading to code execution or privilege escalation during boot.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-20233?
CVE-2021-20233 is a high-severity memory corruption vulnerability in Fedoraproject Fedora, published on 3 Mar 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-787
Which versions are affected by CVE-2021-20233?
It affects 8 products.
Products include Fedoraproject Fedora, Gnu Grub2, Netapp Ontap Select Deploy Administration Utility, Redhat Enterprise Linux, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Eus and 2 more.
How do I fix CVE-2021-20233?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2021-20233 being exploited?
There is no known exploitation of CVE-2021-20233 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in Fedoraproject Fedora
Sources
Also known as ALPINE-CVE-2021-20233, AZL-6466, AZL-78305, DEBIAN-CVE-2021-20233, GHSA-257g-8w4g-3cc3, UBUNTU-CVE-2021-20233.