CVE-2025-55018 is classified as a medium severity vulnerability with a CVSS score of 5.8. This vulnerability allows an unauthenticated attacker to exploit an inconsistent interpretation of HTTP requests, known as 'HTTP request smuggling', within Fortinet FortiOS. Specifically, it affects FortiOS versions 7.6.0, 7.4.0 through 7.4.9, and all versions of FortiOS 7.2, 7.0, and 6.4.3 through 6.4.16.
The potential risk to organizations includes unauthorized access to sensitive data and the ability to bypass firewall policies, making it crucial for affected users to prioritize remediation efforts. Organizations must address this vulnerability immediately to mitigate risks.
The vulnerability was published on February 10, 2026, and has been analyzed by Fortinet. As of now, there are no known exploits publicly available, but organizations should remain vigilant and address this vulnerability in their security posture.
Organizations should prioritize patching immediately.
Vulnerability Details
The official CVE description outlines that this vulnerability allows an unauthenticated attacker to smuggle an unlogged HTTP request through the firewall policies via a specially crafted header. It has been classified under CWE-444, indicating an issue with improper handling of HTTP requests.
The CVSS base score of 5.8 reflects a medium severity, indicating that while exploitation may not be trivial, it is still a concern for organizations using affected FortiOS versions.
Technical Analysis
The root cause of the vulnerability stems from inconsistent interpretation of HTTP requests by the FortiOS firewall. This inconsistency allows attackers to manipulate request headers to bypass security policies.
The attack vector is network-based, with low complexity and no privileges required for exploitation. Additionally, no user interaction is necessary, heightening the risk factor.
Risk & Impact Analysis
Organizations using the affected Fortinet FortiOS versions face a substantial risk of unauthorized access and data exfiltration. The ability to smuggle unlogged requests could lead to broader attacks on the network, making it critical for organizations to address this vulnerability promptly.
Given the CVSS score of 5.8 and the nature of the vulnerability, organizations should address this in their priority patch cycle.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions of Fortinet FortiOS are as follows: FortiOS 7.6.0, FortiOS 7.4.0 through 7.4.9, all versions of FortiOS 7.2, all versions of FortiOS 7.0, and FortiOS 6.4.3 through 6.4.16. Organizations should ensure they upgrade to the latest versions that address this vulnerability.
Mitigation & Remediation
To mitigate this vulnerability, organizations should apply the latest patches from Fortinet. It is recommended to upgrade to the fixed versions of FortiOS as soon as possible.
In case a patch is not immediately available, organizations can implement network controls to restrict unauthorized HTTP requests and monitor their firewall logs for any suspicious activity.
For further guidance on effective remediation strategies, organizations can refer to our penetration testing services.
Detection Guidance
Organizations should monitor their network for unusual HTTP request patterns that may indicate attempts to exploit this vulnerability. Additionally, log indicators should be analyzed for any unauthorized access or anomalies that could suggest an active exploitation.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2025-55018 lies in its demonstration of how even low-severity vulnerabilities can pose substantial risks if left unaddressed. This incident highlights the necessity for continuous monitoring and updating of security measures to adapt to evolving threats.
Organizations should learn from this vulnerability to enhance their security posture. Regular security assessments and penetration testing can help identify vulnerabilities before they can be exploited.
For more insights on vulnerability management, refer to our guides on vulnerability management programs and effective penetration testing methodologies to stay ahead of potential security threats.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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