SB2026021045 - HTTP request smuggling in FortiOS GUI

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Main Vulnerability Database SB2026021045

SB2026021045 - HTTP request smuggling in FortiOS GUI

Published: February 10, 2026

Security Bulletin ID SB2026021045
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Inconsistent interpretation of HTTP requests (CVE-ID: CVE-2025-55018)

CWE-ID: CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:U/U:Green


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.

References