CVE-2025-0686
MediumCVSS 6.4Exploitation Probability (EPSS)
Low risk16th percentile - higher than 16% of all known CVEs
Summary
A flaw in the romfs module of GRUB2 allows integer overflow during buffer size calculation based on user-controlled filesystem geometry parameters. A crafted filesystem can cause a smaller-than-expected buffer allocation, leading to out-of-bounds writes in grub_romfs_read_symlink() and potentially arbitrary code execution.
Risk Assessment
An attacker with physical or local access can execute arbitrary code bypassing Secure Boot protections, potentially leading to full control over the boot process and persistent compromise.
Recommendation
Immediately update GRUB2 to a patched version (e.g., 2.12 or later), re-sign and reinstall the updated bootloader on all systems with Secure Boot enabled.
Original NVD description (English source)
A flaw was found in grub2. When performing a symlink lookup from a romfs filesystem, grub's romfs filesystem module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciously 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_romfs_read_symlink() may cause out-of-bounds writes when the calling grub_disk_read() function. This issue may be leveraged to corrupt grub's internal critical data and can result in arbitrary code execution by-passing secure boot protections.