Information disclosure in urllib3 - CVE-2026-44431
Published: May 9, 2026
Vulnerability identifier: #VU130907
CSH Severity: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-44431
CWE-ID: CWE-200
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
urllib3
urllib3
Software vendor:
urlib3
urlib3
Description
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to exposure of sensitive information in ProxyManager.connection_from_url().urlopen() when following cross-origin redirects with assert_same_host=False through a proxy. A remote attacker can trigger a cross-origin redirect to disclose sensitive information.
Sensitive headers such as Authorization, Cookie, and Proxy-Authorization may be forwarded across origins in this low-level redirect flow.
Remediation
Install security update from vendor's website.