What’s Vulnerable › Vulnerabilities

CVE-2025-55300: Komari Allows Cross-site WebSocket Hijacking

• Severity: high (CVSS 8.6 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-08-18 · updated 2026-06-17
• Weakness: CWE-79

Description

Komari is a lightweight, self-hosted server monitoring tool designed to provide a simple and efficient solution for monitoring server performance. Prior to 1.0.4-fix1, WebSocket upgrader has disabled origin checking, enabling Cross-Site WebSocket Hijacking (CSWSH) attacks against authenticated users. Any third party website can send requests to the terminal websocket endpoint with browser's cookies, resulting in remote code execution. This vulnerability is fixed in 1.0.4-fix1.

Affected products

• komari-monitor komari: before 1.0.4-fix1

References

• https://github.com/komari-monitor/komari/commit/d31d12e59febce100ab0285b93338f09aa5d6cb1
• https://github.com/komari-monitor/komari/security/advisories/GHSA-q355-h244-969h

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