CVE-2025-64471 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 core issue arises from the authentication mechanism improperly accepting a password hash in place of the actual password, categorized under CWE-836 (Use of Password Hash Instead of Password for Authentication). This flaw allows an unauthenticated attacker to craft HTTP or HTTPS requests that leverage the password hash to bypass normal authentication controls. The vulnerability enables escalation of privilege, granting the attacker unauthorized access to the FortiWeb management interface or other protected functions. The CVSS v3.1 base score is 4.4 (medium), reflecting that the attack vector is network-based (AV:N), requires low attack complexity (AC:L), but requires high privileges (PR:H) which indicates some prior access or conditions might be needed, no user interaction (UI:N), and impacts integrity (I:H) without affecting confidentiality or availability. The vulnerability is exploitable remotely without user interaction, but the attacker must craft specific requests to exploit the flaw. No public exploits or active exploitation in the wild have been reported as of the publication date (December 9, 2025). FortiWeb appliances are widely deployed in enterprise environments to protect web applications from attacks, making this vulnerability significant for organizations relying on Fortinet's security infrastructure. The lack of available patches at disclosure necessitates immediate mitigation through compensating controls until vendor updates are released.

For European organizations, the impact of CVE-2025-64471 can be substantial, particularly for those using FortiWeb appliances to secure critical web applications and infrastructure. Successful exploitation allows attackers to escalate privileges within the FortiWeb device, potentially enabling unauthorized configuration changes, bypassing security policies, or gaining deeper network access. This compromises the integrity of the security controls, increasing the risk of further attacks such as data manipulation or lateral movement within the network. Although confidentiality and availability are not directly impacted, the loss of integrity in security appliances can indirectly lead to data breaches or service disruptions. Organizations in sectors like finance, government, healthcare, and telecommunications, which heavily rely on Fortinet products for web application protection, face elevated risks. The vulnerability's network-based attack vector means that attackers can attempt exploitation remotely, increasing the threat surface. However, the requirement for crafted requests and some privilege conditions may limit widespread exploitation. Still, the absence of patches at disclosure heightens the urgency for European entities to implement interim protective measures.

1. Immediately implement network segmentation to restrict access to FortiWeb management interfaces, limiting exposure to trusted administrative networks only. 2. Deploy strict firewall rules and access control lists (ACLs) to block unauthorized HTTP/HTTPS traffic targeting FortiWeb devices. 3. Enable and monitor detailed logging on FortiWeb appliances to detect anomalous authentication attempts or unusual request patterns indicative of exploitation attempts. 4. Use intrusion detection/prevention systems (IDS/IPS) with updated signatures to identify and block crafted requests exploiting this vulnerability. 5. Establish a vulnerability management process to track Fortinet advisories and apply patches or firmware updates as soon as they become available. 6. Conduct regular security audits and penetration tests focusing on FortiWeb configurations and access controls. 7. Educate network and security teams about this vulnerability to ensure rapid response and incident handling. 8. Consider deploying multi-factor authentication (MFA) for FortiWeb administrative access to add an additional security layer, mitigating risks from compromised credentials or hashes. 9. If possible, temporarily disable remote management interfaces or restrict them to VPN access until patches are applied. 10. Collaborate with Fortinet support for guidance and early access to patches or workarounds.