CVE-2025-64447 is a vulnerability identified in multiple versions of Fortinet's FortiWeb web application firewall (WAF) product, specifically versions 7.0.0 through 8.0.1. The root cause is FortiWeb's reliance on cookies for session or operation validation without implementing sufficient validation or integrity checking mechanisms. This design flaw allows an unauthenticated attacker, who must have prior knowledge of the FortiWeb device's serial number, to craft HTTP or HTTPS requests containing forged cookies. These malicious requests can bypass normal security controls and execute arbitrary operations on the FortiWeb system, effectively escalating privileges without authentication. The vulnerability affects the confidentiality, integrity, and availability of the FortiWeb device and potentially the protected web applications. The CVSS v3.1 base score is 7.1, indicating high severity, with an attack vector of network (AV:N), high attack complexity (AC:H), no privileges required (PR:N), and no user interaction (UI:N). The scope remains unchanged (S:U), but the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). Although no public exploits have been reported, the vulnerability's characteristics make it a critical concern for organizations relying on FortiWeb for web application security. The lack of patch links suggests that remediation may require vendor updates or configuration changes once available.

For European organizations, this vulnerability poses a significant risk, especially for those deploying FortiWeb appliances to protect critical web applications and infrastructure. Exploitation could allow attackers to gain unauthorized control over FortiWeb devices, potentially leading to interception or manipulation of web traffic, bypassing security policies, or disrupting service availability. This could result in data breaches, service outages, or further lateral movement within networks. Given FortiWeb's role in securing web applications, successful exploitation could undermine trust in protected services and expose sensitive customer or business data. The requirement for prior knowledge of the serial number somewhat limits the attack surface but does not eliminate risk, as serial numbers can sometimes be discovered through information leakage or reconnaissance. European sectors such as finance, government, healthcare, and telecommunications, which heavily rely on web application firewalls, are particularly vulnerable. Additionally, the high complexity of attack may reduce immediate widespread exploitation but should not lead to complacency.

European organizations should immediately inventory their FortiWeb deployments to identify affected versions (7.0.0 through 8.0.1). Until official patches are released by Fortinet, organizations should implement compensating controls such as restricting network access to FortiWeb management interfaces to trusted IPs only, employing strict firewall rules, and monitoring for anomalous HTTP/HTTPS requests with suspicious cookie values. Fortinet customers should engage with vendor support to obtain patches or recommended configuration changes as soon as they become available. Additionally, organizations should enhance logging and alerting on FortiWeb devices to detect potential exploitation attempts, including unusual cookie usage or unauthorized operations. Regularly updating device firmware and applying security best practices for web application firewall deployment will reduce exposure. Finally, organizations should conduct penetration testing and vulnerability assessments focusing on FortiWeb to validate the effectiveness of mitigations and detect any exploitation attempts.