Vulnerability identifier: #VU51193

Vulnerability risk: Low

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

CVE-ID: CVE-2020-27749

CWE-ID: CWE-121

Exploitation vector: Local

Exploit availability: No

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 grub_parser_split_cmdline() function while expanding variable names present in the supplied command line in to their corresponding variable contents. A local privileged user can run a specially crafted program to trigger the stack-based buffer overflow and bypass Secure Boot protection.

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.