CVE-2020-28903: Improper input validation in Nagios Fusion 4.1.8 and earlier allows a remote attacker with control over a f...

Security readout for executives and security teams

Nagios Fusion 4.1.8 and earlier can display attacker-supplied HTML from a fused server. In business terms, a compromised or malicious monitored server could tamper with what administrators see in Fusion, enabling cross-site scripting risks in a privileged monitoring console. Exposure is most likely where Nagios Fusion 4.1.8 or earlier is deployed and consumes data from fused servers outside strong administrative control. Internet exposure of Fusion administration interfaces would increase business risk, but the bundle does not state that internet access is required. Treat this as a targeted monitoring-console risk, not a broad unauthenticated internet worm scenario based on the provided evidence. Prioritize if Fusion is used for critical operations, has many administrators, or trusts servers outside one security boundary. Mitigation focus: Inventory Nagios Fusion deployments and identify versions at or below 4.1.8.; Check Nagios vendor guidance and change logs for fixed versions or recommended updates.; Remove or quarantine untrusted fused server relationships until reviewed..

Prepared

Jun 2, 2026, 19:53 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.