SB2026021045 - HTTP request smuggling in FortiOS GUI
Published: February 10, 2026
Security Bulletin ID
SB2026021045
Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Inconsistent interpretation of HTTP requests (CVE-ID: CVE-2025-55018)
The vulnerability allows a remote attacker to perform HTTP request smuggling attacks.
The vulnerability exists due to improper validation of HTTP requests in FortiOS GUI. A remote attacker can smuggle an unlogged HTTP request through the firewall policies via a specially crafted header.
Successful exploitation of vulnerability may allow an attacker to poison HTTP cache and perform phishing attacks.
Remediation
Install update from vendor's website.