CVE-2025-13016 is a vulnerability identified in the JavaScript WebAssembly component of Mozilla Firefox prior to version 145 and Firefox ESR prior to version 140.5. The root cause is incorrect boundary condition checks within the WebAssembly engine, which can lead to memory corruption. This flaw can be exploited remotely by an attacker who entices a user to visit a maliciously crafted web page or web content that leverages WebAssembly. Successful exploitation can result in arbitrary code execution with the privileges of the user running the browser, potentially leading to full system compromise, data theft, or denial of service. The vulnerability has a CVSS v3.1 base score of 7.5, indicating high severity. The attack vector is network-based, but requires user interaction (e.g., visiting a malicious website). The attack complexity is high, meaning exploitation is not trivial but feasible for skilled attackers. No privileges or authentication are required, increasing the attack surface. Currently, no known exploits have been reported in the wild, but the presence of this vulnerability in a widely used browser component makes it a significant risk. The lack of available patches at the time of disclosure necessitates immediate attention to updates once released. The WebAssembly component is critical as it enables near-native performance for web applications, making this vulnerability particularly impactful for modern web environments.

For European organizations, the impact of CVE-2025-13016 can be substantial. Many enterprises rely on Firefox for web access, including sensitive internal and cloud-based applications that utilize WebAssembly for performance. Exploitation could lead to unauthorized access to confidential information, manipulation or destruction of data, and disruption of services. Sectors such as finance, healthcare, government, and critical infrastructure are particularly vulnerable due to the sensitive nature of their data and operations. The vulnerability could be leveraged in targeted phishing campaigns or drive-by downloads, increasing the risk of widespread compromise. Additionally, the high integration of web technologies in European digital services amplifies the potential damage. The lack of known exploits currently provides a window for proactive mitigation, but the risk remains high given the ease of remote exploitation once a patch is available.

European organizations should immediately prioritize upgrading Mozilla Firefox to version 145 or Firefox ESR 140.5 or later once patches are available. Until then, organizations should consider implementing the following measures: 1) Restrict or monitor WebAssembly execution through browser policies or enterprise security controls to limit exposure. 2) Employ network-level protections such as web filtering and intrusion detection systems to block access to known malicious sites. 3) Educate users on the risks of interacting with untrusted web content and phishing attempts. 4) Utilize endpoint detection and response (EDR) tools to identify suspicious browser behavior indicative of exploitation attempts. 5) Maintain up-to-date backups and incident response plans to mitigate potential damage from successful attacks. 6) Monitor Mozilla security advisories closely for patch releases and apply them promptly. 7) Consider temporary use of alternative browsers with no known vulnerabilities in WebAssembly components if immediate patching is not feasible.