HTTP Request Smuggling Affecting python3-h11 package, versions <0:0.12.0-2.1.el9ost


Severity

Recommended
0.0
high
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.58% (47th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-RHEL8-PYTHON3H11-9903689
  • published29 Apr 2025
  • disclosed24 Apr 2025

Introduced: 24 Apr 2025

CVE-2025-43859  (opens in a new tab)
CWE-444  (opens in a new tab)

How to fix?

Upgrade RHEL:8 python3-h11 to version 0:0.12.0-2.1.el9ost or higher.
This issue was patched in RHSA-2025:7536.

NVD Description

Note: Versions mentioned in the description apply only to the upstream python3-h11 package and not the python3-h11 package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

h11 is a Python implementation of HTTP/1.1. Prior to version 0.16.0, a leniency in h11's parsing of line terminators in chunked-coding message bodies can lead to request smuggling vulnerabilities under certain conditions. This issue has been patched in version 0.16.0. Since exploitation requires the combination of buggy h11 with a buggy (reverse) proxy, fixing either component is sufficient to mitigate this issue.

CVSS Base Scores

version 3.1