CVE-2025-61663 is a vulnerability identified in the GRUB2 bootloader component of Red Hat Enterprise Linux 10. The flaw is a use-after-free condition occurring in the 'normal' command implementation. Specifically, when the module containing the 'normal' command is unloaded, the command is not properly unregistered, leaving a dangling pointer. If an attacker can execute the 'normal' command after module unload, the system attempts to access memory that has already been freed, leading to undefined behavior. This typically manifests as system instability or a crash, resulting in a denial of service (DoS). The vulnerability has a CVSS 3.1 base score of 4.9, indicating medium severity, with an attack vector of local (AV:L), high attack complexity (AC:H), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), and low impacts on confidentiality, integrity, and availability (C:L/I:L/A:L). Although the primary impact is availability due to system crashes, the possibility of data integrity or confidentiality compromise cannot be fully excluded. Exploitation requires local access and the ability to execute the GRUB 'normal' command, which may limit exposure. No public exploits or active exploitation have been reported to date. The vulnerability was reserved on 2025-09-29 and published on 2025-11-18. No patches or mitigations have been linked yet, but Red Hat is expected to release updates. This vulnerability affects Red Hat Enterprise Linux 10 installations that use GRUB2 as the bootloader, which is common in enterprise Linux environments.

For European organizations, the primary impact of CVE-2025-61663 is the risk of denial of service due to system crashes during boot or runtime when the GRUB2 'normal' command is invoked improperly. This can lead to downtime of critical servers or infrastructure, affecting business continuity and operational availability. Although the confidentiality and integrity impacts are rated low, the instability could potentially be leveraged in complex attack chains to escalate privileges or cause data corruption. Organizations running Red Hat Enterprise Linux 10 in production environments, especially those with local user access or multi-tenant systems, are at risk. Critical sectors such as finance, healthcare, energy, and government that rely on RHEL 10 for secure and stable operations may experience disruptions. The requirement for local access and high attack complexity reduces the likelihood of widespread exploitation but does not eliminate insider threat or targeted attack risks. The absence of known exploits in the wild currently limits immediate threat but patching and mitigation remain important to prevent future exploitation.

To mitigate CVE-2025-61663, European organizations should: 1) Monitor Red Hat security advisories closely and apply patches promptly once released to address the use-after-free flaw in GRUB2. 2) Restrict local access to systems running RHEL 10 to trusted personnel only, minimizing the risk of an attacker executing the vulnerable 'normal' command. 3) Implement strict access controls and auditing around bootloader configuration and command execution to detect and prevent unauthorized use. 4) Consider deploying host-based intrusion detection systems (HIDS) to monitor for anomalous GRUB command invocations. 5) For virtualized or multi-tenant environments, isolate administrative access and limit the ability to modify bootloader settings. 6) Maintain regular backups and recovery plans to reduce downtime impact in case of system crashes. 7) Educate system administrators about the vulnerability and the importance of controlling local access and bootloader interactions. 8) Evaluate the use of secure boot mechanisms and firmware protections to reduce attack surface related to bootloader manipulation. These targeted steps go beyond generic advice by focusing on controlling local execution paths and bootloader command usage specific to this vulnerability.