CVE-2025-0684: gnu grub2 Out-of-bounds Write

Vulnerability summary

CVE-2025-0684 is a medium (CVSS 6.4) Out-of-bounds Write vulnerability in gnu grub2. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 18.7% of scored vulnerabilities.

Timeline

1. 03-03-2025
   PublishedVulnerability first disclosed.
2. 29-06-2026
   Last modifiedVulnerability information updated.

Description

A flaw was found in grub2. When performing a symlink lookup from a reiserfs filesystem, grub's reiserfs fs module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciouly crafted filesystem may lead some of those buffer size calculations to overflow, causing it to perform a grub_malloc() operation with a smaller size than expected. As a result, the grub_reiserfs_read_symlink() will call grub_reiserfs_read_real() with a overflown length parameter, leading to a heap based out-of-bounds write during data reading. This flaw may be leveraged to corrupt grub's internal critical data and can result in arbitrary code execution, by-passing secure boot protections.

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