HTTP Request Smuggling Affecting python-tornado package, versions <6.0.3+really5.1.1-3ubuntu0.1~esm6


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.38% (30th percentile)

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  • Snyk IDSNYK-UBUNTU2004-PYTHONTORNADO-19866306
  • published13 Oct 2026
  • disclosed15 Sept 2026

Introduced: 15 Sep 2026

CVE-2023-54397  (opens in a new tab)
CWE-444  (opens in a new tab)

How to fix?

Upgrade Ubuntu:20.04 python-tornado to version 6.0.3+really5.1.1-3ubuntu0.1~esm6 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream python-tornado package and not the python-tornado package as distributed by Ubuntu. See How to fix? for Ubuntu:20.04 relevant fixed versions and status.

Tornado before 6.3.3 contains an HTTP request smuggling vulnerability due to improper parsing of Content-Length headers accepting non-standard characters. Attackers can send crafted HTTP requests with these characters to bypass proxy validation and smuggle requests when deployed behind certain proxies.

CVSS Base Scores

version 3.1