CVE-2025-51495 is an integer overflow vulnerability identified in the WebSocket component of the Mongoose embedded web server, specifically affecting versions 7.5 through 7.17. The vulnerability arises when the WebSocket implementation processes specially crafted requests that cause an integer overflow. This overflow can lead to a crash of the application using the vulnerable Mongoose component. More critically, if downstream vendors integrate this component improperly, the integer overflow may escalate into a buffer overflow condition, which could potentially allow an attacker to execute arbitrary code or cause further memory corruption. The vulnerability does not require authentication or user interaction, as it can be triggered by sending a malicious WebSocket request directly to the affected server. Although no known exploits are currently reported in the wild, the nature of the vulnerability—affecting a widely used embedded web server component—makes it a significant concern. The lack of a CVSS score suggests that the vulnerability is newly published and may not yet have been fully assessed in terms of impact and exploitability. The vulnerability primarily affects applications and devices that embed Mongoose versions 7.5 to 7.17 with WebSocket support enabled, which are commonly found in IoT devices, network appliances, and industrial control systems. Improper integration by downstream vendors increases the risk of severe exploitation, including remote code execution through buffer overflow. This vulnerability highlights the importance of secure coding practices and thorough security testing when integrating third-party components.

For European organizations, the impact of CVE-2025-51495 could be significant, especially for those relying on IoT devices, industrial control systems, or network appliances that embed the vulnerable Mongoose WebSocket component. A successful exploitation could lead to denial of service via application crashes, disrupting critical services and operations. In cases where downstream vendors have improperly integrated the component, the risk escalates to potential remote code execution, which could compromise the confidentiality, integrity, and availability of affected systems. This is particularly concerning for sectors such as manufacturing, energy, healthcare, and telecommunications, which often use embedded systems with WebSocket capabilities. Disruption or compromise of these systems could lead to operational downtime, data breaches, and safety risks. Additionally, the lack of known exploits currently does not preclude future attacks, especially as threat actors may develop exploits once the vulnerability details become widely known. European organizations with supply chains involving embedded device manufacturers should be vigilant, as vulnerabilities in third-party components can propagate through the ecosystem, affecting a broad range of devices and applications.

To mitigate the risks posed by CVE-2025-51495, European organizations should take several specific actions beyond generic patching advice: 1) Identify and inventory all devices and applications that embed Mongoose versions 7.5 through 7.17 with WebSocket support, including those supplied by third-party vendors. 2) Engage with vendors and suppliers to confirm whether their products are affected and to obtain patches or updated versions that address the integer overflow vulnerability. 3) Where patches are not yet available, implement network-level controls such as WebSocket traffic filtering and anomaly detection to block or monitor suspicious WebSocket requests that could trigger the vulnerability. 4) Conduct thorough security testing and code review for any in-house or third-party software that integrates Mongoose to ensure proper handling of WebSocket requests and to prevent buffer overflow conditions. 5) Employ runtime protections such as memory corruption mitigations (e.g., ASLR, DEP) on affected systems to reduce the impact of potential exploitation. 6) Monitor security advisories and threat intelligence feeds for updates on exploit development and apply patches promptly once available. 7) Implement robust incident response plans to quickly detect and respond to any exploitation attempts involving this vulnerability.