CVE-2024-47742 is a vulnerability identified in the Linux kernel's firmware loader component, specifically related to path traversal attacks. The firmware loader is responsible for loading firmware files required by various hardware devices. The vulnerability arises because certain firmware file names are constructed using strings that originate from device descriptors or semi-privileged userspace inputs without sufficient validation. This allows an attacker to potentially craft firmware file names containing ".." path components, enabling directory traversal and unauthorized access to files outside the intended firmware directory. The kernel code paths affected include firmware file name construction in lpfc_sli4_request_firmware_update(), which uses a model name parsed from device Vital Product Data; nfp_net_fw_find(), which uses a model name from hardware info descriptors; and module_flash_fw_schedule(), which can be triggered via the ETHTOOL_MSG_MODULE_FW_FLASH_ACT netlink command requiring CAP_NET_ADMIN privileges in a user namespace. The vulnerability is mitigated by rejecting any firmware names containing ".." components, preventing directory traversal. The researcher notes that USB device drivers do not appear to use the firmware loader in a way that exposes this vulnerability. Exploitation requires some level of privilege, such as CAP_NET_ADMIN in a network namespace for certain paths, limiting the attack surface. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

For European organizations, this vulnerability poses a moderate risk primarily to systems running vulnerable Linux kernel versions that handle firmware updates via the affected code paths. Successful exploitation could allow an attacker with limited privileges (e.g., CAP_NET_ADMIN in a user namespace) to perform path traversal attacks, potentially leading to unauthorized file access or firmware manipulation. This could compromise system integrity by loading malicious firmware or accessing sensitive files, potentially causing device malfunction or persistent compromise. Confidentiality could be impacted if unauthorized file reads occur. Availability impacts are possible if firmware updates are corrupted or devices fail. However, the requirement for specific privileges and the constrained attack vectors reduce the likelihood of widespread exploitation. Organizations relying on Linux-based infrastructure with network devices using lpfc or nfp drivers, or those allowing user namespaces with CAP_NET_ADMIN, should be particularly cautious. Industrial control systems, telecom infrastructure, and data centers using such hardware could be affected. The absence of known exploits and the patch availability reduce immediate risk but timely patching is critical to prevent future exploitation.

1. Apply the latest Linux kernel patches that address CVE-2024-47742 as soon as they become available from your Linux distribution vendor. 2. Audit and restrict CAP_NET_ADMIN capabilities in user namespaces to only trusted users and processes, minimizing the risk of privilege escalation or misuse. 3. Monitor and control firmware update mechanisms, especially for devices using lpfc and nfp drivers, ensuring firmware file names are validated and sanitized. 4. Implement strict access controls and logging around netlink commands such as ETHTOOL_MSG_MODULE_FW_FLASH_ACT to detect and prevent unauthorized firmware flashing attempts. 5. Conduct regular security assessments of network namespaces and container environments to ensure no unnecessary privileges are granted. 6. Educate system administrators about this vulnerability and the importance of validating firmware sources and update procedures. 7. For critical infrastructure, consider additional runtime integrity monitoring of firmware and device behavior to detect anomalies potentially caused by malicious firmware loading.