CVE-2019-16786 Information

Description

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.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Reference

https://access.redhat.com/errata/RHSA-2020:0720 https://docs.pylonsproject.org/projects/waitress/en/latest/security-fixes https://github.com/Pylons/waitress/commit/f11093a6b3240fc26830b6111e826128af7771c3 https://github.com/Pylons/waitress/security/advisories/GHSA-g2xc-35jw-c63p https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GVDHR2DNKCNQ7YQXISJ45NT4IQDX3LJ7/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LYEOTGWJZVKPRXX2HBNVIYWCX73QYPM5/

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

HIGH

Base Score

NONE

Base Severity

7.5