CVE-2023-52507 is a vulnerability identified in the Linux kernel's NFC (Near Field Communication) subsystem, specifically within the NCI (NFC Controller Interface) protocol handling code. The issue arises from insufficient validation of the protocol value used as a bitmask to determine supported NFC protocols. The kernel code asserts that the provided protocol value is less than the maximum defined protocol index to prevent an out-of-bounds bit shift operation. Without this validation, an attacker could supply an invalid or undefined protocol value, potentially causing a shift operation beyond the bounds of the bitmask. This could lead to unpredictable kernel behavior such as assertion failures or kernel panics, resulting in denial of service (DoS). The patch resolves this by enforcing the protocol value check, ensuring that only valid protocol indices are processed, thereby preventing out-of-bounds shifts and providing clearer error handling for unsupported protocols. The vulnerability affects Linux kernel versions prior to the patch commit identified by the hash 6a2968aaf50c7a22fced77a5e24aa636281efca8. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned yet. The vulnerability is rooted in a logic error in kernel code that handles NFC protocol validation, which is a relatively narrow attack surface but critical for systems utilizing NFC functionality.

For European organizations, the primary impact of CVE-2023-52507 is a potential denial of service on Linux systems with NFC capabilities. This could affect devices such as point-of-sale terminals, access control systems, or embedded devices that rely on NFC for authentication or communication. A successful exploitation could cause kernel crashes, leading to system downtime and disruption of services. While this vulnerability does not appear to allow privilege escalation or remote code execution, the loss of availability in critical infrastructure or commercial environments could have operational and reputational consequences. Organizations in sectors such as retail, transportation, and government that use NFC-enabled Linux devices may be particularly impacted. However, since the vulnerability requires interaction with the NFC subsystem and presumably local or proximate access to the NFC interface, the attack vector is somewhat limited. The absence of known exploits reduces immediate risk but does not eliminate the need for timely patching to prevent future exploitation.

European organizations should prioritize updating their Linux kernels to versions that include the patch for CVE-2023-52507. Since the vulnerability is in the NFC subsystem, organizations should audit their use of NFC on Linux devices and disable NFC functionality where it is not required to reduce the attack surface. For devices that must use NFC, ensure strict access controls and monitoring of NFC interfaces to detect anomalous protocol requests. Additionally, implement kernel crash monitoring and automated recovery mechanisms to minimize downtime in case of exploitation. Security teams should also review device firmware and software that interacts with the NFC stack to ensure they do not inadvertently trigger the vulnerability. Finally, maintain up-to-date inventories of Linux systems with NFC capabilities to facilitate rapid patch deployment and incident response.