#VU64057 Out-of-bounds write in grub - CVE-2021-3695

Vulnerability identifier: #VU64057

Vulnerability risk: Low

CVSSv4.0: 4 [CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-3695

CWE-ID: CWE-787

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 privileged user to bypass implemented security restrictions.

The vulnerability exists due to a boundary error when processing PNG grayscale images. A local privileged user can pass specially crafted PNG image to the application, trigger an out-of-bounds write error and potentially bypass secure boot protection mechanism.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

grub: 1.99 - 2.06

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External links
https://lists.gnu.org/archive/html/grub-devel/2022-06/msg00035.html

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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.