CVE-2026-44431

Description

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.

CVSS Metrics

• v4.0•HIGH•Score: 8.2CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
• v4.0•HIGH•Score: 8.2CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
• v3.1•MEDIUM•Score: 5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS Trends

Current EPSS score: 0.53%• Percentile: 41%

Techniques & Countermeasures

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

  The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

Affected Systems

• PyPI•urllib3

  ≥ 1.23, < 2.7.0

• python•urllib3

  ≥ 1.23, < 2.7.0

• urllib3•urllib3

  ≥ 1.23, < 2.7.0

References (4)

• https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc
• https://github.com/urllib3/urllib3
• https://nvd.nist.gov/vuln/detail/CVE-2026-44431
• https://lists.debian.org/debian-lts-announce/2026/06/msg00040.html