CVE-2025-27535 is a firmware vulnerability identified in Intel(R) Ethernet Connection E825-C network adapters, specifically in versions prior to NVM 3.84. The flaw arises from an exposed ioctl interface within the firmware operating at Ring 0 on Bare Metal OS environments, which lacks sufficient access control. This vulnerability allows a system software adversary possessing privileged user rights on the local machine to trigger a denial of service condition. The attack vector requires local access with elevated privileges and is characterized by high complexity, meaning exploitation demands significant technical skill and understanding of the system internals. No user interaction or special internal knowledge is necessary, but the attacker must have privileged access, which limits the attack surface to insiders or compromised accounts. The vulnerability impacts system availability by potentially causing the network adapter or system to become unresponsive or crash, but it does not compromise confidentiality or integrity of data. The CVSS 4.0 score is 5.6 (medium severity), reflecting the local attack vector, high complexity, and the requirement for privileged access. No known exploits have been reported in the wild to date. The vulnerability is relevant primarily to environments running Bare Metal OS with the affected Intel Ethernet hardware, commonly found in enterprise servers, data centers, and network infrastructure.

For European organizations, the primary impact of CVE-2025-27535 is the potential for denial of service on critical network infrastructure components that utilize Intel Ethernet Connection E825-C adapters with vulnerable firmware. This can lead to network outages, degraded service availability, and operational disruptions, particularly in data centers, cloud service providers, and enterprises relying on high-availability networking. Although confidentiality and integrity are not directly affected, the loss of availability can have cascading effects on business continuity, especially for sectors such as finance, telecommunications, healthcare, and government services. The requirement for privileged local access reduces the risk of remote exploitation but increases the threat from insider attacks or attackers who have already compromised administrative credentials. Given the widespread use of Intel network adapters in European IT infrastructure, the vulnerability poses a tangible risk to service reliability if unpatched.

To mitigate CVE-2025-27535, organizations should prioritize updating the firmware of Intel Ethernet Connection E825-C adapters to version NVM 3.84 or later, where the vulnerability is addressed. Firmware updates should be deployed following rigorous testing in staging environments to avoid unintended disruptions. Additionally, organizations should enforce strict access controls to limit privileged user accounts and monitor for unauthorized privilege escalations or local access attempts. Implementing robust endpoint security measures, including host-based intrusion detection and regular auditing of privileged user activities, can reduce the risk of exploitation. Network segmentation and isolation of critical infrastructure can further contain potential impacts. Since no known exploits exist in the wild, proactive patching combined with enhanced monitoring provides effective risk reduction. Finally, organizations should maintain an inventory of affected hardware to ensure comprehensive coverage during remediation.