CVE-2026-44431 PUBLISHED

urllib3: Sensitive headers forwarded across origins in proxied low-level redirects

Assigner: GitHub_M
Reserved: 06.05.2026 Published: 13.05.2026 Updated: 13.05.2026

urllib3 is an HTTP client library for Python. From 1.23 to before 2.7.0, cross-origin redirects followed from the low-level API via ProxyManager.connection_from_url().urlopen(..., assert_same_host=False) still forward these sensitive headers. This vulnerability is fixed in 2.7.0.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CVSS Score: 8.2

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	High	Integrity	None	Integrity	None
Attack Requirements	Present	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	urllib3
Product	urllib3
Versions	Version >= 1.23, < 2.7.0 is affected

References

https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc

Problem Types

CWE-200: Exposure of Sensitive Information to an Unauthorized Actor CWE