Posting Date: 2026/09/17

【Vulnerability Alert】FortiMonitorOnSight Contains a Critical Security Vulnerability (CVE-2026-84390)

  • Subject:【Vulnerability Alert】FortiMonitorOnSight Contains a Critical Security Vulnerability (CVE-2026-84390)


  • Description:
    • Forwarded from TWCERT/CC Security Advisory TWCERTCC-200-202609-00000014
    • The FortiMonitorOnSight Web portal has a sensitive information exposure in source code vulnerability (CVE-2026-84390, CVSS: 9.6). This vulnerability may allow unauthenticated remote attackers to bypass authentication by spoofing or reusing JWTs.
  • Affected Platforms:
    • FortiMonitorOnSight versions 7.2.0 through 7.2.2
    • FortiMonitorOnSight versions 7.2.4 through 7.2.7
  • Recommended Actions:
    • Please update to the following version: FortiMonitorOnSight 7.2.8 and later
  • References:
    1. https://www.twcert.org.tw/tw/cp-169-11196-1a15a-1.html

Computer and Communication Center
Network System Division