CVE-2023-52797 is a vulnerability identified in the Linux kernel, specifically within the performance monitoring subsystem (perf driver). The issue arises from improper handling of the return value of the function find_first_bit(). This function is used to locate the first set bit in a bitmap, and its return value is subsequently used as an index into an array. However, if the return value is not properly validated, it can overflow the array bounds, leading to a kernel panic. The vulnerability manifests as a fatal exception during interrupt handling, causing the kernel to crash and stop secondary CPUs, resulting in a denial of service (DoS) condition. The provided kernel panic logs indicate the fault occurs in the pmu_sbi_ovf_handler function, which is part of the performance monitoring unit (PMU) handling on RISC-V architectures. The root cause is the lack of a boundary check on the index derived from find_first_bit(), which can lead to out-of-bounds memory access and kernel instability. This vulnerability affects Linux kernel versions identified by the commit hash 4905ec2fb7e6421c14c9fb7276f5aa92f60f2b98 and likely other versions with similar code. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet. The issue was publicly disclosed on May 21, 2024, and a patch is implied but not linked in the provided data. The vulnerability is relevant to systems running Linux kernels with the affected perf driver code, particularly on RISC-V platforms but potentially impacting other architectures if similar code paths exist.

For European organizations, this vulnerability poses a risk primarily in environments running Linux-based systems with the affected kernel versions, especially those utilizing performance monitoring features. The impact is mainly a denial of service due to kernel panic, which can disrupt critical services, cause system downtime, and potentially affect availability of infrastructure. Organizations relying on Linux servers for cloud services, data centers, or embedded systems could experience service interruptions. While the vulnerability does not directly lead to privilege escalation or data leakage, the forced kernel panic can be exploited by attackers to cause repeated crashes, impacting operational continuity. This is particularly significant for sectors with high availability requirements such as finance, healthcare, telecommunications, and critical infrastructure. The lack of requirement for user interaction or authentication to trigger the vulnerability increases the risk profile, as local or potentially remote attackers with access to the system could exploit it. However, the absence of known exploits in the wild suggests the threat is currently theoretical but should be addressed proactively to avoid future exploitation.

European organizations should prioritize updating their Linux kernels to versions where this vulnerability is patched. Since the issue stems from improper validation of find_first_bit() return values in the perf driver, applying the official Linux kernel patches or vendor-provided updates is the most effective mitigation. Organizations should: 1) Identify all Linux systems running affected kernel versions, especially those on RISC-V architectures or using performance monitoring features. 2) Test and deploy kernel updates from trusted sources promptly. 3) If immediate patching is not feasible, consider disabling or restricting access to the perf subsystem or performance monitoring features to reduce attack surface. 4) Monitor system logs for kernel panics or unusual crashes that could indicate attempted exploitation. 5) Implement robust system monitoring and alerting to detect and respond to denial of service conditions quickly. 6) For critical systems, consider employing kernel live patching solutions to minimize downtime during patch deployment. 7) Engage with Linux distribution vendors for guidance and timely security updates. These steps go beyond generic advice by focusing on the specific subsystem and kernel versions affected, emphasizing proactive detection and controlled mitigation in operational environments.