PyPI: urllib3

CVE-2018-25091

Safety vulnerability ID: SFTY-20231015-86742

Safety legacy ID: pyup.io-71562

Affected versions of urllib3 affected versions are vulnerable due to an issue where the authorization HTTP header is not removed when following a cross-origin redirect. This can result in credentials within the authorization header being exposed to unintended hosts or transmitted in cleartext. This vulnerability exists because of an incomplete fix for CVE-2018-20060, which addressed a similar issue case-sensitively.

Created at: Nov 6, 2025Updated at: Nov 6, 2025

Overview

Authorization Header forwarded on redirect

Advisory

Affected versions of urllib3 affected versions are vulnerable due to an issue where the authorization HTTP header is not removed when following a cross-origin redirect. This can result in credentials within the authorization header being exposed to unintended hosts or transmitted in cleartext. This vulnerability exists because of an incomplete fix for CVE-2018-20060, which addressed a similar issue case-sensitively.

Affected Package

Affecting urllib3 package, versions
<1.24.2

Also affects

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How to Fix

Upgrade
urllib3
to
1.24.2
or higher.

Mitigation and Workarounds

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Vulnerable Functions

Functions linked to known vulnerabilities.

Vulnerable function data is available for Enterprise customers

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Safety

Verified by Safety

Our Cybersecurity Intelligence Team reviewed this vulnerability. We combine public data with our own research to find issues not yet reported to public sources.

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