HTTP Request Smuggling Affecting py3-h11 package, versions <0.16.0-r0


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.58% (47th percentile)

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  • Snyk IDSNYK-MINIMOSLATEST-PY3H11-13306944
  • published6 Oct 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 Minimos:latest py3-h11 to version 0.16.0-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream py3-h11 package and not the py3-h11 package as distributed by Minimos. See How to fix? for Minimos:latest 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