CVE-2025-54770 is a Use-after-Free vulnerability identified in the GNU GRUB2 bootloader, specifically within its network module. The root cause is that the net_set_vlan command, which configures VLAN settings for network interfaces during boot, is not properly unregistered when the network module is unloaded from memory. This improper cleanup results in pointers referencing freed memory areas. When an attacker with the ability to execute the net_set_vlan command triggers this condition, the system attempts to access invalid memory locations, causing instability and ultimately a denial of service (DoS) through system crash or halt. The vulnerability requires local access to the system and has a high attack complexity, meaning it is not trivial to exploit remotely or without specific privileges. The CVSS v3.1 score is 4.9 (medium severity), reflecting limited confidentiality and integrity impact but a direct effect on availability. No authentication is required, but the attacker must have the capability to execute the vulnerable command, which is typically restricted. There are no known exploits in the wild at the time of publication, and no patches have been linked yet. The vulnerability affects GRUB2 versions marked as '0' in the data, which likely indicates all versions prior to a fix or a placeholder. Given GRUB2's widespread use in Linux-based systems, especially servers and embedded devices, this vulnerability could impact a broad range of environments where network boot or VLAN configuration is used during system startup.

For European organizations, the primary impact of CVE-2025-54770 is on system availability. Systems using GRUB2 with network modules enabled and VLAN configurations are susceptible to denial of service attacks that can cause system crashes, leading to downtime. This can disrupt critical services, particularly in sectors such as telecommunications, finance, healthcare, and government infrastructure that rely heavily on Linux-based servers and network boot capabilities. Although the vulnerability does not directly compromise confidentiality or integrity, the resulting outages can cause operational disruptions and potential financial losses. The requirement for local access limits the threat to insiders or attackers who have already gained some foothold in the network, reducing the risk of widespread remote exploitation. However, in environments where physical or privileged access is possible, such as data centers or managed service providers, the risk is more pronounced. The lack of known exploits in the wild currently reduces immediate threat levels but does not eliminate the need for vigilance and timely remediation.

To mitigate CVE-2025-54770, organizations should implement several specific measures beyond generic patching advice. First, restrict access to systems' bootloader commands and network configuration interfaces to trusted administrators only, minimizing the risk of unauthorized command execution. Second, disable or limit the use of the GRUB2 network module and VLAN configuration during boot if not required, reducing the attack surface. Third, monitor system logs and bootloader activity for unusual net_set_vlan command invocations that could indicate exploitation attempts. Fourth, prepare to apply patches promptly once they are released by GNU or Linux distribution vendors, as no official patch links are currently available. Fifth, incorporate bootloader integrity checks and secure boot mechanisms to prevent unauthorized modifications or command injections during startup. Finally, conduct regular security audits and penetration testing focusing on bootloader and network module configurations to identify potential weaknesses before exploitation.