PT-2026-39665 · Pypi · Urllib3

Christos-Spearbit

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Published

2026-05-11

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Updated

2026-06-03

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CVE-2026-44431

CVSS v4.0

8.2

High

VectorAV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
Name of the Vulnerable Software and Affected Versions urllib3 versions 1.23 through 2.6.x
Description Sensitive headers, specifically Authorization, Cookie, and Proxy-Authorization, are forwarded during cross-origin redirects when using the low-level API via ProxyManager.connection from url().urlopen(..., assert same host=False). While high-level APIs like urllib3.request(), PoolManager.request(), and ProxyManager.request() strip these headers by default, the low-level flow fails to do so.
Recommendations Upgrade to version 2.7.0 or later. Avoid using the low-level redirect flow for cross-origin redirects or switch to ProxyManager.request().

Fix

Information Disclosure

Weakness Enumeration

Related Identifiers

CLEANSTART-2026-AN27706
CLEANSTART-2026-EP51501
CLEANSTART-2026-GH89210
CLEANSTART-2026-HZ86045
CLEANSTART-2026-LZ07533
CLEANSTART-2026-MV15822
CLEANSTART-2026-QK55639
CLEANSTART-2026-UV23635
CVE-2026-44431
ECHO-4544-3B20-7E41
GHSA-QCCP-GFCP-XXVC
OESA-2026-2298
OESA-2026-2299
OESA-2026-2300
OESA-2026-2390
OESA-2026-2391
OPENSUSE-SU-2026:10838-1
PYSEC-2026-141
USN-8379-1

Affected Products

Urllib3