CVE-2024-36976 is a vulnerability identified in the Linux kernel related to a recent patch that introduced a potential deadlock scenario in the media subsystem, specifically within the Video4Linux2 (v4l2) controls. The vulnerability stems from a commit (9801b5b28c6929139d6fceeee8d739cc67bb2739) that modified the way owned controls are shown in the log_status function. This change inadvertently created an unsafe locking order between two locks: (hdl_vid_cap)->_lock and (hdl_user_vid)->_lock. The deadlock occurs when two CPUs attempt to acquire these locks in opposite orders, leading to a situation where each CPU waits indefinitely for the other to release a lock, causing a system hang or freeze in the affected subsystem. The Linux kernel maintainers have reverted this commit to eliminate the deadlock risk. This vulnerability does not appear to have any known exploits in the wild and does not directly expose confidentiality or integrity risks but rather affects system availability by potentially causing kernel-level deadlocks. The issue is specific to the media subsystem and the handling of video capture controls, which may impact systems using video capture devices or media applications relying on the v4l2 framework. Since the vulnerability is in the kernel, it affects all Linux distributions that incorporated the vulnerable commit. The fix involves reverting the problematic commit, indicating that the vulnerability is a regression introduced by a recent patch rather than a longstanding flaw.

For European organizations, the primary impact of CVE-2024-36976 is on system availability and stability, particularly for servers or workstations that utilize video capture hardware or media processing applications dependent on the Linux kernel's v4l2 subsystem. Organizations in sectors such as media production, broadcasting, video conferencing, and any industry relying on Linux-based video capture solutions may experience system hangs or crashes if the vulnerable kernel version is deployed. While the vulnerability does not lead to data breaches or privilege escalations, the potential for deadlocks can disrupt critical services, leading to operational downtime and productivity loss. In environments with high availability requirements, such as financial institutions, healthcare providers, or public services, even transient deadlocks can have significant operational consequences. Additionally, embedded Linux devices used in surveillance, industrial control, or IoT applications that utilize video capture could be affected, potentially impacting security monitoring or automated processes. However, since no known exploits exist and the vulnerability requires specific kernel versions with the problematic commit, the overall risk is moderate but should not be ignored.

To mitigate the risk posed by CVE-2024-36976, European organizations should: 1) Immediately verify if their Linux systems are running kernel versions containing the vulnerable commit (9801b5b28c6929139d6fceeee8d739cc67bb2739). 2) Apply the official kernel update or patch that reverts the problematic commit as soon as it becomes available from their Linux distribution vendor or kernel maintainers. 3) For custom or embedded Linux systems, rebuild the kernel excluding the vulnerable commit or apply the revert patch manually. 4) Conduct thorough testing of media and video capture functionalities post-patch to ensure stability and no regressions. 5) Monitor system logs for signs of deadlocks or hangs related to the v4l2 subsystem and implement proactive alerting. 6) In environments where immediate patching is not feasible, consider disabling or limiting the use of video capture devices or applications that trigger the vulnerable code paths as a temporary workaround. 7) Maintain an up-to-date inventory of Linux kernel versions deployed across the organization to facilitate rapid vulnerability assessments and patch management. These steps go beyond generic advice by focusing on kernel version verification, targeted patch application, and operational monitoring specific to the media subsystem.