CVE-2025-37791 is a vulnerability identified in the Linux kernel's ethtool component, specifically within the cmis_cdb module. The issue arises from incorrect handling of the size parameter for the 'rpl' pointer in the function ethtool_cmis_module_poll(). Instead of using the correct size of the data pointed to by 'rpl' (which should be 1 byte), the code erroneously uses the size of the pointer itself. This discrepancy leads to stack corruption during execution. The stack corruption manifests as a kernel panic with the message 'stack-protector: Kernel stack is corrupted' occurring in the ethtool_cmis_wait_for_cond() function. The vulnerability is triggered during operations related to module firmware updates, as indicated by the call trace involving module_flash_fw_work and ethtool_cmis_fw_update(). The kernel panic and stack corruption can cause the affected system to crash, resulting in denial of service. The vulnerability is rooted in a programming error that mishandles pointer size, leading to memory corruption on the kernel stack. This flaw affects Linux kernel versions identified by the commit hash a39c84d796254e6b1662ca0c46dbc313379e9291. There is no indication that this vulnerability requires user interaction or authentication to be exploited, nor are there known exploits in the wild at the time of publication. However, the impact of exploitation is severe due to the kernel panic and potential system instability or downtime. No CVSS score has been assigned yet, and no official patches or mitigations are linked in the provided data.

For European organizations, the impact of CVE-2025-37791 can be significant, especially for those relying on Linux servers and infrastructure that utilize the ethtool utility for network device management and firmware updates. The vulnerability can cause kernel panics leading to system crashes and denial of service, which may disrupt critical services, including web hosting, cloud services, and internal network operations. Organizations in sectors such as finance, healthcare, telecommunications, and government, which often depend on Linux-based systems for their IT infrastructure, could face operational disruptions and potential data availability issues. The stack corruption could also be leveraged as a foothold for further kernel-level attacks if combined with other vulnerabilities, although no such exploits are currently known. Given the kernel-level nature of the flaw, recovery from crashes may require system reboots, potentially impacting service-level agreements (SLAs) and causing downtime. The lack of authentication requirements means that local or potentially remote attackers with access to vulnerable systems could trigger the issue, increasing the risk profile. Additionally, the vulnerability affects Dell PowerEdge servers as indicated by the hardware in the example, which are commonly used in enterprise environments across Europe, further elevating the risk to critical infrastructure.

European organizations should take proactive steps to mitigate this vulnerability beyond generic advice. First, they should monitor Linux kernel updates closely and prioritize applying patches once they become available from trusted sources or Linux distributions. Until patches are released, organizations should audit their use of ethtool, especially any automated firmware update processes involving the cmis_cdb module, and consider disabling or restricting these operations if feasible. Implement strict access controls to limit who can execute ethtool commands or perform firmware updates on network devices. Employ kernel crash monitoring and alerting to detect and respond rapidly to any kernel panics that may indicate exploitation attempts. For critical systems, consider deploying kernel live patching solutions if supported by the distribution to minimize downtime when applying fixes. Additionally, conduct thorough testing of firmware update workflows in controlled environments to identify potential triggers of the vulnerability. Network segmentation and limiting administrative access to management interfaces can reduce the attack surface. Finally, maintain up-to-date backups and disaster recovery plans to ensure rapid restoration in case of system crashes caused by exploitation.