CVE-2024-20687 is a high-severity vulnerability identified as an out-of-bounds read (CWE-125) in the Microsoft AllJoyn API component of Windows 10 Version 1809 (build 10.0.17763.0). The AllJoyn API is a framework facilitating communication between devices and applications, often used in IoT and local network scenarios. This vulnerability allows an unauthenticated remote attacker to cause a denial of service (DoS) condition by sending specially crafted network packets that trigger an out-of-bounds read in the affected API. The vulnerability does not impact confidentiality or integrity but results in availability disruption by crashing or destabilizing the affected system. The CVSS v3.1 base score is 7.5, reflecting a network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no confidentiality or integrity impact (C:N/I:N), but high impact on availability (A:H). No known exploits are currently reported in the wild, and no official patches or mitigation links have been published yet. The vulnerability was reserved in late November 2023 and published in January 2024. Given the affected product is Windows 10 Version 1809, which is an older release, the exposure is limited to systems still running this version, which may be found in legacy or specialized environments.

For European organizations, the primary impact of CVE-2024-20687 is the potential for denial of service attacks against systems running Windows 10 Version 1809 that utilize the AllJoyn API. This could disrupt critical services, especially in industrial, IoT, or enterprise environments where AllJoyn-enabled applications facilitate device communication. Availability loss could lead to operational downtime, impacting productivity and service delivery. Since the vulnerability requires no authentication or user interaction and can be triggered remotely, attackers could exploit it over the network, increasing risk in exposed environments. However, the lack of confidentiality or integrity impact limits data breach concerns. Organizations with legacy systems or those that have not migrated from Windows 10 Version 1809 are at higher risk. The absence of known exploits reduces immediate threat but does not eliminate the risk of future exploitation. Disruption in sectors relying on IoT or device interoperability, such as manufacturing, healthcare, or smart building management, could be significant if these systems are affected.

To mitigate CVE-2024-20687, European organizations should prioritize upgrading or patching affected systems. Since no official patch links are currently available, organizations should monitor Microsoft security advisories closely for updates. In the interim, network-level mitigations can reduce exposure: restrict or block inbound traffic to the AllJoyn API ports and protocols using firewalls or network segmentation, especially from untrusted networks. Disable the AllJoyn API service on Windows 10 Version 1809 systems if it is not required, to eliminate the attack surface. Conduct an inventory to identify systems running Windows 10 Version 1809 and assess their exposure. Employ intrusion detection systems (IDS) or anomaly detection to monitor for unusual network activity targeting AllJoyn services. Additionally, plan and execute migration to supported Windows versions to reduce legacy vulnerabilities. Implement strict network access controls and isolate legacy systems from critical infrastructure where possible.