SB2026021044 - Firewall policy bypass in FortiOS FSSO Terminal Services Agent
Published: February 10, 2026
Security Bulletin ID
SB2026021044
CSH Severity
Low
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 vulnerability.
1) Improper verification of source of a communication channel (CVE-ID: CVE-2025-62439)
CWE-ID: CWE-940 - Improper Verification of Source of a Communication Channel
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear
The vulnerability allows a remote user to gain unauthorized access to protected network.
The vulnerability exists due to firewall policy bypass in FSSO Terminal Services Agent. A remote authenticated user with knowledge of FSSO policy configurations can gain unauthorized access to protected network resources via crafted requests.
Remediation
Install update from vendor's website.