CVE-2021-3695

Publication date 6 July 2022

Last updated 24 July 2024

Ubuntu priority

Cvss 3 Severity Score

A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent secure boot protections. This issue has a high complexity to be exploited as an attacker needs to perform some triage over the heap layout to achieve signifcant results, also the values written into the memory are repeated three times in a row making difficult to produce valid payloads. This flaw affects grub2 versions prior grub-2.12.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
grub2	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Not affected
	22.04 LTS jammy	Not affected
	21.10 impish	Ignored
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not affected
grub2-signed	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Ignored
	22.04 LTS jammy	Fixed 1.187.3~22.04.1
	20.04 LTS focal	Fixed 1.187.3~20.04.1
	18.04 LTS bionic	Fixed 1.187.3~18.04.1
	16.04 LTS xenial	Vulnerable
	14.04 LTS trusty	Vulnerable
grub2-unsigned	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Ignored
	22.04 LTS jammy	Fixed 2.06-2ubuntu14.1
	20.04 LTS focal	Fixed 2.06-2ubuntu14.1
	18.04 LTS bionic	Fixed 2.06-2ubuntu14.1
	16.04 LTS xenial	Vulnerable
	14.04 LTS trusty	Not in release

Severity score breakdown

Parameter	Value
Base score	4.5 · Medium
Attack vector	Local
Attack complexity	High
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality	Low
Integrity impact	Low
Availability impact	Low
Vector	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L

References

Related Ubuntu Security Notices (USN)