CVE-2021-20233

grub2: Heap out-of-bounds write due to miscalculation of space required for quoting

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Severity

Moderate

Red Hat Product Security

7.5

CVSS 3.1

Review impact separately from score.

Published · March 3, 2021

Updated · June 27, 2026

Description

A flaw was found in grub2. 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.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

No mitigation is specified in collected source.

CVSS / CWE

CVSS 3.1 · 7.5
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

CWE-787 · Out-of-bounds Write