CVE-2025-62675 Fortinet CVE debrief

Who should care

Organizations using Fortinet FortiOS and FortiProxy, especially those with exposure to untrusted users or interfaces, should prioritize patching vulnerable versions to prevent potential HTTP response splitting attacks. This includes reviewing current deployments, assessing exposure, and ensuring proper security controls are in place. Security teams should also monitor for suspicious link clicks and header injections, and consider compensating controls like web application firewalls for exposed systems while remediation is scheduled and verified. Additionally, verifying and updating the inventory of Fortinet products is crucial for maintaining security posture. Operators and platforms using these products must assess their vulnerability management processes to ensure timely patching and mitigation of affected systems. This vulnerability management is critical for maintaining the security and integrity of affected systems and networks. Security teams should track exceptions, retest remediated assets, and close the item only after evidence is documented. This proactive approach will help in minimizing potential risks associated with this vulnerability. Therefore, it is essential for affected organizations to take immediate action to secure their systems and prevent potential attacks. The vulnerability's impact on security teams and operators necessitates a thorough review of current security measures and the implementation of additional controls as needed. By prioritizing patching and implementing compensating controls, organizations can effectively manage the risks associated with this vulnerability and protect their systems from potential attacks. Security teams must also consider the operational impact of this vulnerability and take steps to mitigate it. This includes reviewing and updating incident response plans, as well as conducting regular security audits to identify and address potential vulnerabilities. By taking a proactive and comprehensive approach to security, organizations can minimize the risks associated with this vulnerability and maintain the security and integrity of their systems and networks. The affected products and their versions are as 7.6

Technical summary

CVE-2025-62675 is an Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting') vulnerability affecting Fortinet FortiOS 7.6.0 through 7.6.4, FortiOS 7.4 all versions, FortiOS 7.2 all versions, FortiProxy 7.6.0 through 7.6.4, FortiProxy 7.4 all versions, FortiProxy 7.2 all versions. An attacker with a valid web filter override token may inject arbitrary headers by tricking a user into clicking on a crafted link.

Defensive priority

Organizations using Fortinet FortiOS and FortiProxy should prioritize patching vulnerable versions to prevent potential HTTP response splitting attacks.

Recommended defensive actions

• Apply patches for Fortinet FortiOS 7.6.0 through 7.6.4, FortiOS 7.4 all versions, FortiOS 7.2 all versions, FortiProxy 7.6.0 through 7.6.4, FortiProxy 7.4 all versions, FortiProxy 7.2 all versions.
• Restrict access to web filter override tokens.
• Monitor for suspicious link clicks and header injections.
• Verify and update inventory of Fortinet products.
• Consider compensating controls like web application firewalls.

Evidence notes

The CVE record indicates an Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting') vulnerability in Fortinet FortiOS and FortiProxy. An attacker with a valid web filter override token could inject arbitrary headers by tricking a user into clicking on a crafted link. This vulnerability affects Fortinet FortiOS 7.6.0 through 7.6.4, FortiOS 7.4 all versions, FortiOS 7.2 all versions, FortiProxy 7.6.0 through 7.6.4, FortiProxy 7.4 all versions, FortiProxy 7.2 all versions. The attack requires user interaction and possession of a valid web filter override token. Defenders should verify affected product deployments, review official advisories, and plan vendor-supported updates or mitigations.

Official resources