Fortinet patched 10 vulnerabilities including two critical authentication flaws, CVE-2026-84390 (CVSS 9.6) and CVE-2026-84388 (CVSS 9.1), in FortiMonitorOnSight and the FortiPAM Chrome extension.
Fortinet's September patch release fixes CVE-2026-84390, a sensitive-information issue in the FortiMonitorOnSight web portal that lets unauthenticated attackers bypass authentication with forged or reused JWTs. CVE-2026-84388 is an improper authentication flaw in the Fortinet Privileged Access Agent Chrome extension that can allow attackers to proxy a user's browser traffic via a malicious website, requiring upgrades to both FortiPAM 1.9.1/1.8.4 and extension 8.0.1.123+. High-severity information disclosure in FortiSandbox (CVE-2026-26084) and man-in-the-middle risk in the FortiOS/FortiProxy Agentless ZTNA portal (CVE-2026-84393) were also fixed, alongside medium/low issues across FortiManager, FortiAnalyzer, FortiSOAR, FortiClient, FortiSIEM and others. Fortinet did not indicate any of the flaws are being exploited in the wild.