Medium [CVE-2025-0677] Grub2: ufs: integer overflow may lead to heap based out-of-bounds write when handling symlinks

A flaw was found in grub2. When performing a symlink lookup, the grub's UFS module checks the inode's data size to allocate the internal buffer to read the file content, however, it fails to check if the symlink data size has overflown.

When this occurs, grub_malloc() may be called with a smaller value than needed. When further reading the data from the disk into the buffer, the grub_ufs_lookup_symlink() function will write past the end of the allocated size.

An attack can leverage this by crafting a malicious filesystem, and as a result, it will corrupt data stored in the heap, allowing for arbitrary code execution used to by-pass secure boot mechanisms. Red Hat Product Security has rated this vulnerability with Moderate severity, as it requires high privileges to exploit.

Weakness: CWE-787. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 9; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat OpenShift Container Platform 4.

Will not fix / out of support: Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8. Red Hat fixing advisory: RHSA-2025:16154, RHSA-2025:6990.

Affected products named by the advisory: Red Hat package: grub2.