Medium CVSS 6.7

Overview

When reading data from a hfs filesystem, grub's hfs filesystem module uses user-controlled parameters from the filesystem metadata to calculate the internal buffers size, however it misses to properly check for integer overflows. A maliciouly crafted filesystem may lead some of those buffer size calculation to overflow, causing it to perform a grub_malloc() operation with a smaller size than expected. As a result the hfsplus_open_compressed_real() function will write past of the internal buffer length. This flaw may be leveraged to corrupt grub's internal critical data and may result in arbitrary code execution by-passing secure boot protections.

Risk analysis

This vulnerability is rated 🟡 MEDIUM.

  • CVSS: 6.7 (MEDIUM)
  • Detected tags: int_overflow, rce (tag impact: VERY HIGH)

Recommended actions:

  • Patch/upgrade immediately (remote code execution).
  • Reduce exposure (WAF/segmentation), minimize attack surface.

Recommended tools

Tags