CVE-2023-23559 is a high-severity vulnerability identified in the Linux kernel, specifically within the rndis_query_oid function located in the drivers/net/wireless/rndis_wlan.c source file. This vulnerability exists in Linux kernel versions up to and including 6.1.5. The root cause is an integer overflow during an addition operation. Integer overflows occur when an arithmetic operation attempts to create a numeric value that is outside the range that can be represented with a given number of bits, causing the value to wrap around unexpectedly. In this context, the overflow can lead to incorrect memory allocation or buffer size calculations, potentially enabling an attacker to perform out-of-bounds memory writes or reads. The vulnerability is classified under CWE-190 (Integer Overflow or Wraparound). The CVSS v3.1 base score is 7.8, indicating a high severity level. The vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H reveals that the attack vector requires local access (AV:L), low attack complexity (AC:L), and low privileges (PR:L), with no user interaction (UI:N). The scope is unchanged (S:U), but the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). This means an attacker with local access and low privileges can exploit this vulnerability without user interaction to gain full control over the affected system, potentially leading to privilege escalation or arbitrary code execution. No known exploits in the wild have been reported yet, and no official patches are linked in the provided information, but given the kernel version affected, it is likely that patches have been or will be released in subsequent kernel updates. The vulnerability affects the RNDIS (Remote Network Driver Interface Specification) wireless driver component, which is used for network communication over USB interfaces, often in embedded or mobile devices running Linux kernels.

For European organizations, this vulnerability poses a significant risk, especially for those relying on Linux-based systems with wireless networking capabilities that utilize the RNDIS driver. This includes enterprise servers, embedded systems, IoT devices, and mobile devices running vulnerable Linux kernels. Exploitation could allow local attackers or malicious insiders to escalate privileges, compromise system confidentiality, integrity, and availability, and potentially move laterally within networks. Critical infrastructure sectors such as telecommunications, manufacturing, and government agencies that deploy Linux-based network equipment or embedded devices are particularly at risk. The high impact on confidentiality, integrity, and availability means sensitive data could be exfiltrated or manipulated, and system operations disrupted. Given the local attack vector, physical or local network access is required, which may limit remote exploitation but does not eliminate risk in environments with shared access or insufficient network segmentation. The absence of user interaction requirement facilitates automated exploitation once local access is obtained. The lack of known exploits in the wild currently reduces immediate risk but does not preclude future exploitation, especially as proof-of-concept code may emerge.

European organizations should take proactive steps to mitigate this vulnerability beyond generic patching advice. First, they should inventory all Linux systems to identify those running kernel versions up to 6.1.5 that include the vulnerable RNDIS driver. Immediate kernel upgrades to versions where this vulnerability is patched should be prioritized. If upgrading is not immediately feasible, organizations should consider disabling the RNDIS wireless driver if it is not required, to reduce the attack surface. Network segmentation and strict access controls should be enforced to limit local access to trusted users only, minimizing the risk of local exploitation. Monitoring and logging of local access attempts and unusual network driver activity can help detect exploitation attempts early. For embedded and IoT devices, coordination with vendors to obtain patched firmware or kernel updates is critical. Additionally, organizations should implement strict privilege management to reduce the number of users with local low-level access and consider employing kernel hardening techniques such as SELinux or AppArmor profiles to restrict driver behavior. Finally, security teams should stay informed about any emerging exploit code or patches related to this vulnerability and apply updates promptly.