CVE-2019-16786

Publication date 20 December 2019

Last updated 26 August 2025

Ubuntu priority

Cvss 3 Severity Score

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.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
waitress	25.10 questing	Not affected
	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Not affected
	22.04 LTS jammy	Not affected
	21.10 impish	Not affected
	21.04 hirsute	Not affected
	20.10 groovy	Not affected
	20.04 LTS focal	Not affected
	19.10 eoan	Ignored end of life
	19.04 disco	Ignored end of life
	18.04 LTS bionic	Vulnerable
	16.04 LTS xenial	Vulnerable
	14.04 LTS trusty	Not in release

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
waitress	Upstream: f11093a

Severity score breakdown

Parameter	Value
Base score	7.1 · High
Attack vector	Network
Attack complexity	High
Privileges required	Low
User interaction	None
Scope	Changed
Confidentiality	High
Integrity impact	Low
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N