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The CVE-2025-64471 vulnerability in Fortinet FortiWeb arises from a flaw in the authentication mechanism where the system incorrectly processes password hashes. Normally, during authentication, a user provides a plaintext password, which is hashed and compared to a stored hash. However, in affected versions, the system fails to distinguish between a provided password and its hash, allowing the hash value to be used directly for authentication. This occurs when handling crafted HTTP/HTTPS requests to the FortiWeb management interface or application protection features. The vulnerability stems from improper input validation in the authentication code path, where the received credential is treated as a password without verifying if it is already a hash. Attackers can exploit this by obtaining password hashes through other means, such as database leaks or network sniffing, and then submitting these hashes in authentication requests. The system mistakenly hashes the provided hash again or compares it directly to stored hashes, leading to a match. This bypasses the need for password cracking, enabling unauthenticated attackers to gain access as legitimate users. The flaw affects multiple FortiWeb versions due to shared codebase in authentication modules. It leverages CWE-836, where using a hash instead of the password simplifies attack vectors. Crafted requests can target login endpoints, API interfaces, or administrative portals, using tools like curl or custom scripts. The vulnerability is critical because it allows full authentication bypass without brute force, potentially compromising the entire FortiWeb device. Patches must ensure that only plaintext passwords are accepted and hashed server-side for comparison.
Platform: Fortinet FortiWeb
Version: Versions 7.0.0-8.0.1
Vulnerability: Password hash authentication flaw
Severity: Critical
Date: 12/09/2025
Prediction: Patch expected December 2025
What Undercode Say:
Analytics:
Check FortiWeb version via curl
curl -k https://
Simulate authentication with hash
curl -X POST https://
Bash script to test vulnerability
if [[ $(curl -s -o /dev/null -w “%{http_code}” https://
How Exploit:
Craft HTTP POST requests with password hashes in credential fields, targeting login endpoints. Use tools like Burp Suite or curl to inject hashes obtained from leaks or reconnaissance. Bypass authentication to gain admin privileges or access protected resources.
Protection from this CVE:
Update to patched versions, implement network segmentation, use multi-factor authentication, monitor authentication logs for hash-like patterns, and apply Fortinet security advisories.
Impact:
Unauthorized access, data breach, system compromise, privilege escalation, and potential ransomware deployment.
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Sources:
Reported By: nvd.nist.gov
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