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.
https://www.oracle.com/security-alerts/cpuapr2022.html
https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html
https://github.com/Pylons/waitress/security/advisories/GHSA-g2xc-35jw-c63p
https://github.com/Pylons/waitress/commit/f11093a6b3240fc26830b6111e826128af7771c3
https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes
Published: 2019-12-20
Updated: 2023-11-07
Base Score: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N
Severity: Medium
Base Score: 7.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Severity: High
Base Score: 5.1
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N
Severity: Medium