CVE-2023-52576 is a medium-severity vulnerability in the Linux kernel related to improper memory management in the x86 architecture's memory management (mm) subsystem, specifically involving the kexec and Integrity Measurement Architecture (IMA) components. The issue arises because the function ima_free_kexec_buffer() is called after the memblock allocator has already been torn down. Memblock is a low-level memory allocator used during early boot stages. Calling ima_free_kexec_buffer() at this late stage leads to a use-after-free condition in the function memblock_isolate_range(). When Kernel Address Sanitizer (KASAN) or Kernel Electric Fence (KFENCE) debugging tools are enabled, this use-after-free triggers a BUG in the idle task, causing a kernel panic and system crash. The root cause is that the memory is freed too late, and the fix involves switching the call to memblock_free_late(), which safely frees memory after the allocator teardown, preventing the use-after-free. This vulnerability is identified as CWE-416 (Use After Free). The CVSS 3.1 score is 5.5 (medium), with an attack vector of local (AV:L), low attack complexity (AC:L), requiring low privileges (PR:L), no user interaction (UI:N), unchanged scope (S:U), no impact on confidentiality or integrity (C:N, I:N), but high impact on availability (A:H). No known exploits are reported in the wild as of the publication date (March 2, 2024).

For European organizations relying on Linux-based systems, especially those using x86 architecture and employing kexec or IMA features, this vulnerability could lead to unexpected kernel panics and system crashes. This impacts system availability, potentially causing downtime for critical infrastructure, servers, or embedded devices running vulnerable kernel versions. Although the attack vector is local and requires low privileges, it could be exploited by an attacker or malicious insider with limited access to cause denial of service. The lack of impact on confidentiality and integrity reduces the risk of data breaches or unauthorized data modification. However, availability disruptions in sectors such as finance, healthcare, telecommunications, and government services could have significant operational and reputational consequences. Systems running with KASAN or KFENCE enabled (typically in testing or debugging environments) are more likely to experience immediate crashes, but production systems without these tools may still be vulnerable to instability or crashes under certain conditions.

European organizations should prioritize updating their Linux kernels to versions that include the patch switching ima_free_kexec_buffer() to memblock_free_late(). Since this is a kernel-level vulnerability, applying vendor-provided kernel updates or patches is the most effective mitigation. Organizations should audit their systems to identify those running affected kernel versions, particularly on x86 platforms using kexec and IMA features. For environments using KASAN or KFENCE, testing the updated kernel is critical to ensure stability. Additionally, limiting local user privileges and access can reduce the risk of exploitation, as the vulnerability requires local access with low privileges. Monitoring system logs for kernel panics or unusual crashes may help detect exploitation attempts. For critical systems, consider implementing redundancy and failover mechanisms to mitigate availability impacts during patching or potential exploitation. Finally, maintain a robust patch management process to quickly deploy kernel updates across all Linux systems.