Cyber Resilience

CVE-2021-20233

High

Published: 03 March 2021

Published
03 March 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 8.2 CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
EPSS Score 0.0029 52.5th percentile
Risk Priority 17 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-20233 is a high-severity Out-of-bounds Write (CWE-787) vulnerability in Redhat Enterprise Linux Server Aus. Its CVSS base score is 8.2 (High).

Operationally, ranked in the top 47.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

gnu
grub2
≤ 2.06
redhat
enterprise linux
7.0, 8.0
redhat
enterprise linux server aus
7.2, 7.3, 7.4, 7.6, 7.7
redhat
enterprise linux server eus
7.6, 7.7, 8.1
redhat
enterprise linux server tus
7.4, 7.6, 7.7, 8.2
redhat
enterprise linux workstation
7.0
fedoraproject
fedora
33, 34
netapp
ontap select deploy administration utility
all versions

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-787

Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.

References