CVE-2019-16786

Waitress through version 1.3.1 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. This issue is fixed in Waitress 1.4.0.

Bugs

• <https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=947306&gt;