CVE-2023-53113 is a vulnerability identified in the Linux kernel's wireless networking subsystem, specifically within the nl80211 component that manages Wi-Fi interfaces. The flaw arises from a NULL pointer dereference in the off-channel check logic. This occurs when the system is operating in Access Point (AP) mode and a wireless link has been created by userspace but not yet activated. In this state, the link possesses a channel definition (chandef) structure; however, this chandef is invalid and lacks a proper channel assignment. The kernel code failed to verify the validity of the chandef before dereferencing it, leading to a NULL pointer dereference. This can cause the kernel to crash or panic, resulting in a denial of service (DoS) condition. The vulnerability affects certain Linux kernel versions identified by specific commit hashes, indicating it is present in recent kernel builds prior to the patch. The issue was addressed by adding a check to ignore links with invalid chandef structures during the off-channel validation process, thereby preventing the NULL pointer dereference. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet. The vulnerability is primarily a stability and availability concern rather than a direct confidentiality or integrity threat, as it can cause system crashes but does not inherently allow code execution or privilege escalation.

For European organizations, this vulnerability poses a risk primarily to the availability and stability of Linux-based systems that utilize Wi-Fi in AP mode, such as wireless routers, access points, embedded devices, and servers running Linux with wireless capabilities. A successful exploitation could lead to kernel crashes, causing service interruptions or downtime. This is particularly critical for enterprises relying on Linux-based infrastructure for networking, telecommunications, or IoT deployments. Disruptions could affect business continuity, especially in sectors like telecommunications, manufacturing, and critical infrastructure where wireless connectivity is integral. Although no active exploits are known, the vulnerability could be leveraged in targeted denial-of-service attacks, potentially by malicious insiders or attackers with network access. The impact on confidentiality and integrity is minimal, but the availability impact could be significant depending on the deployment scale and criticality of affected systems.

To mitigate this vulnerability, European organizations should prioritize updating their Linux kernels to the patched versions that include the fix for CVE-2023-53113. This involves applying vendor-supplied kernel updates or recompiling the kernel with the corrected nl80211 code. Network administrators should audit their wireless infrastructure to identify devices running vulnerable kernel versions, especially those operating in AP mode. Where immediate patching is not feasible, organizations can consider temporarily disabling AP mode on affected devices or restricting wireless management interfaces to trusted administrators to reduce exposure. Additionally, implementing robust monitoring for kernel crashes and system logs can help detect potential exploitation attempts. Organizations should also maintain strict access controls and network segmentation to limit the ability of attackers to reach vulnerable wireless subsystems. Finally, coordinating with Linux distribution vendors and hardware manufacturers to ensure timely patch deployment is critical.