CVE-2023-28466 is a high-severity vulnerability identified in the Linux kernel's TLS implementation, specifically within the function do_tls_getsockopt located in net/tls/tls_main.c. This vulnerability exists in Linux kernel versions up to and including 6.2.6. The root cause is the absence of a lock_sock call, which leads to a race condition during socket option retrieval in the TLS subsystem. This race condition can result in a use-after-free or a NULL pointer dereference. Use-after-free vulnerabilities occur when a program continues to use a pointer after the memory it points to has been freed, potentially allowing attackers to execute arbitrary code, cause a denial of service (system crash), or escalate privileges. A NULL pointer dereference typically leads to a denial of service by crashing the kernel. The vulnerability requires local access with low privileges (PR:L) and has a high attack complexity (AC:H), meaning exploitation is not trivial but feasible under certain conditions. No user interaction is required (UI:N), and the scope is unchanged (S:U), indicating the impact is limited to the vulnerable component. The CVSS v3.1 base score is 7.0, reflecting high severity with high impact on confidentiality, integrity, and availability. No known exploits are currently reported in the wild, and no official patches or vendor-specific product information are provided in the data. The vulnerability is categorized under CWE-476 (NULL Pointer Dereference).

For European organizations, this vulnerability poses a significant risk, especially for those relying on Linux-based infrastructure for critical services, including web servers, application servers, and network appliances that utilize kernel TLS features. Exploitation could lead to system crashes causing denial of service, potentially disrupting business operations and critical services. In worst cases, exploitation might allow privilege escalation or arbitrary code execution, threatening confidentiality and integrity of sensitive data. Given the Linux kernel's widespread use in cloud environments, data centers, and embedded systems across Europe, the vulnerability could affect a broad range of sectors including finance, healthcare, government, and telecommunications. The requirement for local access limits remote exploitation but insider threats or compromised accounts could leverage this vulnerability. The high attack complexity reduces the likelihood of widespread exploitation but does not eliminate targeted attacks against high-value assets. The absence of known exploits suggests that immediate risk is moderate but patching and mitigation remain critical to prevent future exploitation.

European organizations should prioritize updating their Linux kernel to versions beyond 6.2.6 once patches become available from their Linux distribution vendors. Until patches are released, organizations should implement strict access controls to limit local access to trusted users only, minimizing the risk of exploitation. Employ kernel hardening techniques such as Kernel Address Space Layout Randomization (KASLR) and enable security modules like SELinux or AppArmor to reduce the attack surface. Monitoring system logs for unusual kernel crashes or suspicious activity related to TLS socket operations can provide early detection of exploitation attempts. For environments where immediate patching is not feasible, consider disabling kernel TLS offloading features if possible, to mitigate the attack vector. Regularly review and update incident response plans to include scenarios involving kernel-level vulnerabilities. Collaboration with Linux distribution vendors and security communities is advised to stay informed about patch releases and exploit developments.