CVE-2025-27021 is a high-severity vulnerability affecting the Infinera G42 optical transport platform, specifically version R6.1.3. The root cause is a misconfiguration in the sudoers file of the underlying operating system, which grants low-privileged users the ability to execute the 'devmem' command as root without requiring a password. The 'devmem' tool allows direct read and write access to physical memory by specifying absolute addresses. This capability enables an attacker with limited OS privileges to manipulate kernel memory arbitrarily. Such access can lead to multiple severe consequences, including disclosure of sensitive information stored in kernel memory, denial of service by corrupting critical kernel data structures, and privilege escalation by modifying kernel code or data to gain root-level access. The vulnerability is notable because it does not require user interaction and can be exploited locally by any user with low privileges on the device. The CVSS v3.1 base score is 7.0, reflecting high impact on confidentiality, integrity, and availability, though the attack vector is local and requires high attack complexity. No known exploits in the wild have been reported yet, and no patches or mitigations have been linked in the provided data. The vulnerability was published on July 2, 2025, and assigned by ENISA, highlighting its relevance to European cybersecurity stakeholders. The Infinera G42 is a critical component in optical transport networks, used by telecom operators and large enterprises for high-capacity data transmission, making this vulnerability particularly concerning for network infrastructure security.

For European organizations, especially telecom operators, internet service providers, and large enterprises relying on Infinera G42 platforms, this vulnerability poses a significant risk. Exploitation could lead to unauthorized access to sensitive network data, disruption of optical transport services, and potential takeover of network devices. Such impacts can degrade network availability, compromise data confidentiality, and allow attackers to persistently control critical infrastructure. Given the role of optical transport equipment in backbone networks, successful exploitation could cascade into broader network outages or data interception, affecting end-users and critical services. The high integrity and availability impact could disrupt communications and services essential to business operations and public safety. Additionally, the ability to escalate privileges locally means that if an attacker gains any foothold on the device, they can fully compromise it, increasing the threat posed by insider threats or lateral movement from compromised internal systems.

1. Immediate review and correction of the sudoers configuration on Infinera G42 devices to remove or restrict passwordless execution of the 'devmem' command. 2. Implement strict access controls to limit which users have shell or local access to the device, minimizing the risk of low-privileged user exploitation. 3. Monitor and audit usage of privileged commands, especially 'devmem', to detect anomalous activity. 4. Apply any vendor-provided patches or configuration updates as soon as they become available. 5. Employ network segmentation to isolate management interfaces of optical transport devices from general user networks, reducing exposure. 6. Use host-based intrusion detection systems (HIDS) to alert on unauthorized attempts to access physical memory or escalate privileges. 7. Conduct regular security assessments and penetration tests focusing on device configurations and local privilege escalation vectors. 8. Educate operational staff on the risks of misconfigured sudoers files and the importance of least privilege principles in device management.