HTTP Request Smuggling Affecting waitress package, versions [,1.4.0)


Severity

Recommended
0.0
high
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

EPSS
0.34% (71st percentile)

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  • Snyk IDSNYK-PYTHON-WAITRESS-538575
  • published21 Dec 2019
  • disclosed13 Dec 2019
  • creditUnknown

Introduced: 13 Dec 2019

CVE-2019-16786  (opens in a new tab)
CWE-444  (opens in a new tab)

How to fix?

Upgrade waitress to version 1.4.0 or higher.

Overview

waitress is a production-quality pure-Python WSGI server with very acceptable performance.

Affected versions of this package are vulnerable to HTTP Request Smuggling. It would parse the Transfer-Encoding header and only look for a single string value, if that value was not chunked it would fall through and use the Content-Length header instead. According to the HTTP standard Transfer-Encoding should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with chunked. Requests sent with: Transfer-Encoding: gzip, chunked would incorrectly get ignored, and the request would use a Content-Length header instead to determine the body size of the HTTP message. This could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining.

CVSS Scores

version 3.1