CVE-2024-50195 is a vulnerability in the Linux kernel's POSIX clock subsystem, specifically in the function pc_clock_settime(). The issue arises because the kernel did not strictly validate the timespec64 structure's fields (tv_sec and tv_nsec) before passing them to the PTP (Precision Time Protocol) clock driver's settime64() function. The timespec64 struct represents time values with seconds (tv_sec) and nanoseconds (tv_nsec). According to the clock_settime() man page, tv_sec must not be negative and tv_nsec must be within the range 0 to 999,999,999. However, some drivers assumed that these values were already validated by higher layers and used them directly to write hardware registers without additional checks. This assumption is unsafe because invalid time values could lead to undefined behavior or hardware misconfiguration. The fix involves introducing a stricter validation function, timespec64_valid_strict(), in pc_clock_settime() to ensure that the time values are within valid ranges before proceeding. This change prevents invalid time values from reaching hardware drivers such as hclge_ptp_settime(), igb_ptp_settime_i210(), and _rcar_gen4_ptp_settime(), which previously relied on the upper layers for validation. The vulnerability could potentially allow an attacker with the ability to invoke clock_settime() on a PTP clock device to supply malformed time values that might cause incorrect hardware register writes, leading to unpredictable device behavior or denial of service. No known exploits are currently reported in the wild, and the vulnerability requires local privileges to invoke the affected system calls. The affected versions are identified by specific Linux kernel commit hashes, indicating this is a recent fix in the kernel source. No CVSS score has been assigned yet.

For European organizations, this vulnerability primarily affects systems running Linux kernels with PTP hardware clock support, which are common in telecommunications, industrial control systems, financial trading platforms, and other environments requiring precise time synchronization. Misconfigured or maliciously manipulated time settings could disrupt time-sensitive operations, potentially causing data inconsistencies, transaction errors, or service outages. In critical infrastructure sectors such as energy grids or transport systems, inaccurate timekeeping can degrade system reliability and safety. Although exploitation requires local access and the ability to invoke clock_settime() on PTP devices, insider threats or compromised accounts could leverage this flaw to cause denial of service or hardware misbehavior. Since many European enterprises and service providers rely on Linux-based systems for network infrastructure and time synchronization, the vulnerability poses a moderate risk to operational stability if left unpatched. However, the lack of known exploits and the requirement for local privileges reduce the immediate threat level. Still, the potential for hardware-level impact and cascading failures in time-dependent systems warrants prompt attention.

European organizations should prioritize updating their Linux kernels to versions that include the patch for CVE-2024-50195. Specifically, they should track kernel releases incorporating the fix that adds strict timespec64 validation in pc_clock_settime(). For systems where immediate kernel upgrades are not feasible, organizations should restrict access to privileged interfaces that allow modification of PTP clock settings, limiting this capability to trusted administrators only. Monitoring and auditing usage of clock_settime() system calls on PTP devices can help detect anomalous or unauthorized attempts to set invalid time values. Additionally, organizations should review and harden driver-level code if custom or legacy PTP drivers are in use, ensuring they perform their own validation rather than relying solely on upper-layer checks. In environments with critical time synchronization needs, implementing redundant time sources and failover mechanisms can mitigate the impact of potential time-setting disruptions. Finally, organizations should maintain awareness of kernel security advisories and apply patches promptly to minimize exposure.