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

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.2%, percentile 15: FIRST’s model estimates a 0.2% chance of exploitation activity in the next 30 days, higher than 15% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs a user to click or open something. Phishing makes that realistic, but it is not wormable.
• Only applies if your dependency tree includes sillytavern (npm) < 1.13.4, fixed in 1.13.4. Check your lockfile, including transitive dependencies.

What it is

SillyTavern is a locally installed user interface that allows users to interact with text generation large language models, image generation engines, and text-to-speech voice models. In versions prior to 1.13.4, the web user interface for SillyTavern is susceptible to DNS rebinding, allowing attackers to perform actions like install malicious extensions, read chats, inject arbitrary HTML for phishing attacks, etc. The 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 SILLYTAVERNHOSTWHITELISTENABLED 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.

From the GitHub advisory

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 1. Host the PoC HTML file on a /rebind.html endpoint (or any other endpoint) on a web server on port 8000 2. Go to https://lock.cmpxchg8b.com/rebinder.html and input your IP address (A) to rebind to 127.0.0.1 (B) 3. Replace the URL in the HTML with the returned URL on the site 4. Go to http://[URL]:8000/rebind.html in firefox or on any mobile browser if you're using termux 5. Check the developer tools console. It should return all of the data

Here is the PoC code:

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.

Weakness type: CWE-346, CWE-940.

Product: sillytavern (npm) · Assigned by: GitHub_M · Published: 2025-10-06

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: required (a user must click/open something)
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.25% probability of exploitation activity in the next 30 days; percentile 15.

Timeline

• 2025-10-06 — CVE record last updated
• 2025-10-06 — CVE record published by GitHub_M
• 2025-10-06 — GitHub-reviewed advisory GHSA-7cxj-w27x-x78q published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-7cxj-w27x-x78q github.com
2. CVE.org record CVE-2025-59159 cve.org
3. NVD entry CVE-2025-59159 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. docs.sillytavern.app docs.sillytavern.app
4. docs.sillytavern.app docs.sillytavern.app
5. github.com github.com

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