When reading language .mo file in grub_mofile_open(), grub2 fails to verify to a integer overflow when allocating its internal buffer. A crafted .mo file may lead to the buffer size calculation to overflow leading to Out-of-bound reads and writes. An attacker may leverage this flaw to leak sensitive data or overwrite critical data possibly leading to the circumvention of secure boot protections.
This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2025:6990 https://access.redhat.com/errata/RHSA-2025:6990