Vulnerability identifier: #VU51198

Vulnerability risk: Low

CVSSv3.1: 5.8 [CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-20233

CWE-ID: CWE-787

Exploitation vector: Local

Exploit availability: Yes

Vulnerable software:
grub
Universal components / Libraries / Libraries used by multiple products

Vendor: GNU

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a boundary error within the setparam_prefix() function in menu rendering code. A local privileged user can run a specially crafted program to trigger out-of-bounds write and escalate privileges on the system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

grub: 2.00 - 2.06

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External links
http://seclists.org/oss-sec/2021/q1/189

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.