urllib3 v2.2.0-2.5.0 redirect control flaw in Pyodide browser runtimes
CVE-2025-50182 Published on June 19, 2025
urllib3 does not control redirects in browsers and Node.js
urllib3 is a user-friendly HTTP client library for Python. Starting in version 2.2.0 and prior to 2.5.0, urllib3 does not control redirects in browsers and Node.js. urllib3 supports being used in a Pyodide runtime utilizing the JavaScript Fetch API or falling back on XMLHttpRequest. This means Python libraries can be used to make HTTP requests from a browser or Node.js. Additionally, urllib3 provides a mechanism to control redirects, but the retries and redirect parameters are ignored with Pyodide; the runtime itself determines redirect behavior. This issue has been patched in version 2.5.0.
Vulnerability Analysis
CVE-2025-50182 is exploitable with network access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity and availability.
Weakness Type
What is an Open Redirect Vulnerability?
A web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a Redirect. This simplifies phishing attacks. An http parameter may contain a URL value and could cause the web application to redirect the request to the specified URL. By modifying the URL value to a malicious site, an attacker may successfully launch a phishing scam and steal user credentials. Because the server name in the modified link is identical to the original site, phishing attempts have a more trustworthy appearance.
CVE-2025-50182 has been classified to as an Open Redirect vulnerability or weakness.
Products Associated with CVE-2025-50182
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Affected Versions
urllib3 Version >= 2.2.0, < 2.5.0 is affected by CVE-2025-50182Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.