CVE-2025-0677 Grub2: ufs: integer overflow may lead to heap based out-of-bounds write when handling symlinks
An integer overflow in GRUB2's UFS module allows heap corruption and arbitrary code execution, enabling secure boot bypass via a malicious filesystem.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-0677?
CVE-2025-0677 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, published on 19 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-787
Which versions are affected by CVE-2025-0677?
How do I fix CVE-2025-0677?
Apply the vendor's patch.
Is CVE-2025-0677 being exploited?
There is no known exploitation of CVE-2025-0677 in the wild and no public exploit code.
Sources
Also known as AZL-56919, AZL-57007, BELL-CVE-2025-0677, CLSA-2026-1779370563, DEBIAN-CVE-2025-0677, GHSA-h592-gmp8-rvr7 and 1 more.