HTTP Request Smuggling Affecting gunicorn Open this link in a new tab package, versions [,19.10.0) [20.0.0,20.0.1)

  • Attack Complexity


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Introduced: 15 Nov 2019

CWE-444 Open this link in a new tab

How to fix?

Upgrade gunicorn to version 19.10.0, 20.0.1 or higher.


gunicorn is a Python WSGI HTTP Server for UNIX

Affected versions of this package are vulnerable to HTTP Request Smuggling. It fails to properly process the Transfer-Encoding and Content-Length headers when both are present in a package request. This allows for conflicting information to be sent regarding the length of the package, which when processed by back-end servers under certain configurations would allow for malicious users to bypass security controls, gain unauthorized access to sensitive data, and directly compromise other application users.