CVE-2021-3695

Publication date 6 July 2022

Last updated 24 July 2024


Ubuntu priority

Cvss 3 Severity Score

4.5 · Medium

Score breakdown

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

Package Ubuntu Release Status
grub2 24.10 oracular
Not affected
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 end of life
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 24.10 oracular
Not affected
24.04 LTS noble
Not affected
23.10 mantic
Not affected
23.04 lunar
Not affected
22.10 kinetic Ignored end of life
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 Ignored end of ESM support, was needed
grub2-unsigned 24.10 oracular
Not affected
24.04 LTS noble
Not affected
23.10 mantic
Not affected
23.04 lunar
Not affected
22.10 kinetic Ignored end of life
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)

    • USN-6355-1
    • GRUB2 vulnerabilities
    • 8 September 2023

Other references