CVE-2021-3695: fedoraproject fedora Out-of-bounds Write

Vulnerability summary

CVE-2021-3695 is a medium (CVSS 4.5) Out-of-bounds Write vulnerability in fedoraproject fedora. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 38.7% of scored vulnerabilities.

Timeline

1. 06-07-2022
   PublishedVulnerability first disclosed.
2. 03-08-2024
   Last modifiedVulnerability information updated.

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.

• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.