CVE-2021-3695

Description

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.

How to fix CVE-2021-3695

To remediate CVE-2021-3695, upgrade the affected package to a fixed version below.

• —upgrade to 2.06-3~deb11u1 or later

Is CVE-2021-3695 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (1)

• from 0, < 2.06-3~deb11u1

CVSS scores

References (1)

• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2021-3695