CVE-2024-45776 is a vulnerability identified in the GRUB2 bootloader component grub_mofile_open(), which processes language .mo files used for localization. The vulnerability stems from a failure to properly verify integer overflow conditions when allocating an internal buffer size. Specifically, when reading a crafted .mo file, the calculation for the buffer size can overflow, causing the allocation to be smaller than intended. This leads to out-of-bounds memory reads and writes during subsequent processing. Such memory corruption can be leveraged by an attacker to leak sensitive information from memory or overwrite critical data structures. This may include manipulation of secure boot parameters or other bootloader integrity checks, potentially allowing an attacker to bypass secure boot protections. The attack requires local access with high privileges (PR:H) but does not require user interaction (UI:N). The vulnerability affects all versions of GRUB2 that handle .mo files in this manner, though specific affected versions are not detailed. The CVSS v3.1 base score is 6.7, indicating a medium severity with high impact on confidentiality, integrity, and availability. No public exploits are known at this time, but the flaw represents a significant risk in environments where GRUB2 is used and secure boot is critical. The vulnerability was reserved in September 2024 and published in February 2025, with enrichment from CISA indicating its recognized importance.

The primary impact of CVE-2024-45776 is the potential for attackers with local high-level privileges to execute out-of-bounds memory operations within the GRUB2 bootloader. This can lead to leakage of sensitive information, such as cryptographic keys or boot configuration data, compromising confidentiality. Additionally, overwriting critical data structures may allow attackers to alter boot parameters or bypass secure boot protections, undermining system integrity and availability. This could facilitate persistent malware infections or rootkits that load before the OS, evading detection by traditional security controls. Systems relying on GRUB2 for boot management, especially those enforcing secure boot policies, are at risk of having their boot integrity compromised. The requirement for local privileged access limits remote exploitation but does not eliminate risk in multi-user or shared environments. The absence of known exploits reduces immediate threat but patching is essential to prevent future exploitation. Organizations with critical infrastructure, sensitive data, or compliance requirements involving secure boot should consider this vulnerability a significant risk.

To mitigate CVE-2024-45776, organizations should: 1) Monitor vendor advisories and apply GRUB2 patches promptly once released to address the integer overflow and buffer allocation flaw. 2) Restrict local access to systems and ensure only trusted administrators have high privilege levels capable of modifying or injecting .mo files. 3) Harden boot environments by enforcing strict file integrity monitoring on GRUB2 configuration and localization files to detect unauthorized modifications. 4) Implement secure boot policies with hardware root of trust to limit the impact of bootloader compromise. 5) Use system-level protections such as SELinux or AppArmor to constrain GRUB2 processes and limit their ability to perform unauthorized memory operations. 6) Conduct regular audits of bootloader configurations and logs to detect anomalies. 7) Educate system administrators about the risks of loading untrusted localization files or modifying bootloader components. These steps go beyond generic advice by focusing on controlling local privilege access, integrity monitoring of boot components, and layered security controls around the boot process.