HTTP Request Smuggling Affecting python-urllib3 package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.42% (34th percentile)

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  • Snyk IDSNYK-RHEL10-PYTHONURLLIB3-19491005
  • published16 Oct 2026
  • disclosed6 Aug 2026

Introduced: 6 Aug 2026

CVE-2026-71554  (opens in a new tab)
CWE-444  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:10 python-urllib3.

NVD Description

Note: Versions mentioned in the description apply only to the upstream python-urllib3 package and not the python-urllib3 package as distributed by RHEL. See How to fix? for RHEL:10 relevant fixed versions and status.

h2 is a pure-Python implementation of a HTTP/2 protocol stack. Versions up to and including 4.4.0 accept request header blocks containing more than one Host header, and forward every Host header to the consuming application. Where the consumer downgrades HTTP/2 to HTTP/1.1, the resulting request carries two Host header lines, providing a request smuggling primitive. This issue is fixed in version 4.4.1.

CVSS Base Scores

version 3.1