CVE-2025-55300 Komari Allows Cross-site WebSocket Hijacking
Attackers can hijack WebSocket connections to execute remote code on monitored servers via CSRF-like attacks against authenticated users.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-55300?
CVE-2025-55300 is a high-severity vulnerability in komari-monitor komari, published on 18 Aug 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-79
Which versions are affected by CVE-2025-55300?
3 open source packages ship an affected version, including github.com/komari-monitor/komari.
| Package | Affected | Fixed in |
|---|---|---|
github.com/komari-monitor/komari Go | All versions | 0.0.0-20250809073044-53171affcaf0 |
github.com/komari-monitor/komari Go | All versions | 0.0.0-20250809073044-53171affcaf0 |
github.com/komari-monitor/komari Go | All versions | 0.0.0-20250809073044-53171affcaf0 |
How do I fix CVE-2025-55300?
Upgrade github.com/komari-monitor/komari to 0.0.0-20250809073044-53171affcaf0 or later.
Is CVE-2025-55300 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-55300 exists.
Sources
Also known as GHSA-q355-h244-969h, GO-2025-3874.