CVE-2024-23775 is an integer overflow vulnerability identified in the Mbed TLS library versions 2.x prior to 2.28.7 and 3.x prior to 3.5.2. Mbed TLS is a widely used open-source cryptographic library designed for embedded systems and IoT devices, providing SSL/TLS and cryptographic functionalities. The vulnerability arises specifically in the function mbedtls_x509_set_extension(), which is responsible for processing X.509 certificate extensions. An integer overflow occurs when the function improperly handles certain input sizes or values, causing an arithmetic overflow that can lead to memory corruption or unexpected behavior. Exploiting this flaw allows an unauthenticated remote attacker to trigger a denial of service (DoS) condition by causing the affected application to crash or become unresponsive. The CVSS v3.1 base score of 7.5 reflects a high severity, with an attack vector that is network-based (AV:N), requiring no privileges (PR:N) and no user interaction (UI:N). The impact is limited to availability (A:H), with no confidentiality or integrity loss. No known exploits are currently reported in the wild, but the vulnerability's presence in a fundamental cryptographic library means it could affect a broad range of products and services that rely on Mbed TLS for secure communications. This includes embedded devices, IoT products, and network appliances that embed Mbed TLS for TLS/SSL functionality. The vulnerability is classified under CWE-190 (Integer Overflow or Wraparound), indicating a failure to properly validate or constrain integer values during processing.

For European organizations, the impact of CVE-2024-23775 can be significant, especially for sectors relying heavily on embedded systems and IoT devices that use Mbed TLS. Critical infrastructure, telecommunications, manufacturing, and healthcare sectors often deploy devices with embedded cryptographic libraries. A successful DoS attack exploiting this vulnerability could disrupt secure communications, leading to service outages or degraded performance. Although the vulnerability does not directly compromise confidentiality or integrity, the loss of availability can interrupt business operations, cause downtime, and potentially impact safety-critical systems. Given the increasing reliance on IoT and embedded devices in Europe, this vulnerability could affect a wide range of endpoints, from industrial control systems to consumer devices. The lack of authentication or user interaction required for exploitation increases the risk, as attackers can remotely trigger the DoS condition without needing privileged access. Organizations may face challenges in patching embedded devices promptly due to hardware constraints or vendor update cycles, prolonging exposure to the threat.

To mitigate CVE-2024-23775, European organizations should prioritize the following actions: 1) Identify all products and devices within their environment that utilize Mbed TLS versions prior to 2.28.7 or 3.5.2. This may require coordination with vendors and hardware manufacturers to obtain accurate software version information. 2) Apply vendor-supplied patches or firmware updates that incorporate the fixed versions of Mbed TLS. If direct patches are unavailable, consider isolating or segmenting vulnerable devices to limit network exposure. 3) Implement network-level protections such as intrusion detection/prevention systems (IDS/IPS) configured to detect anomalous traffic patterns that could indicate exploitation attempts targeting TLS handshake or certificate processing. 4) Conduct thorough testing of embedded devices and applications to verify the absence of the vulnerability post-update. 5) For devices that cannot be updated promptly, employ compensating controls such as limiting access to trusted networks, enforcing strict firewall rules, and monitoring device health and logs for signs of instability or crashes. 6) Engage with device manufacturers to encourage timely security updates and transparency regarding cryptographic library versions used. 7) Maintain an inventory of embedded and IoT devices to improve visibility and response capabilities for vulnerabilities affecting underlying libraries like Mbed TLS.