CVE-2025-0684: grub2 Memory Corruption (CVSS 6.4)

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.

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CVSS v3.1 Score

6.4

MEDIUM

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-787 Out-of-bounds Write

Affected Products

Vendor	Product	Versions
gnu	grub2	< 2.12

References

Other References

https://access.redhat.com/security/cve/CVE-2025-0684 https://bugzilla.redhat.com/show_bug.cgi?id=2346119

Frequently Asked Questions

What is CVE-2025-0684? +

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. It has a CVSS v3.1 base score of 6.4 (MEDIUM).

How severe is CVE-2025-0684? +

CVE-2025-0684 has a CVSS v3.1 score of 6.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-0684? +

CVE-2025-0684 affects products from gnu, specifically: grub2. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-0684? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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