Waitress through version 1.3.1 implemented a "MAY" part of the RFC7230 which states: "Although the line terminator for the start-line and header fields is the sequence CRLF, a recipient MAY recognize a single LF as a line terminator and ignore any preceding CR." Unfortunately if a front-end server does not parse header fields with an LF the same way as it does those with a CRLF it can lead to the front-end and the back-end server parsing the same HTTP message in two different ways. This can lead to a potential for HTTP request smuggling/splitting whereby Waitress may see two requests while the front-end server only sees a single HTTP message. This issue is fixed in Waitress 1.4.0.
Advisories
Source ID Title
Debian DLA Debian DLA DLA-3000-1 waitress security update
EUVD EUVD EUVD-2019-0156 Waitress through version 1.3.1 implemented a \"MAY\" part of the RFC7230 which states: \"Although the line terminator for the start-line and header fields is the sequence CRLF, a recipient MAY recognize a single LF as a line terminator and ignore any preceding CR.\" Unfortunately if a front-end server does not parse header fields with an LF the same way as it does those with a CRLF it can lead to the front-end and the back-end server parsing the same HTTP message in two different ways. This can lead to a potential for HTTP request smuggling/splitting whereby Waitress may see two requests while the front-end server only sees a single HTTP message. This issue is fixed in Waitress 1.4.0.
Github GHSA Github GHSA GHSA-pg36-wpm5-g57p HTTP Request Smuggling: LF vs CRLF handling in Waitress
Fixes

Solution

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Workaround

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2024-08-05T01:24:47.876Z

Reserved: 2019-09-24T00:00:00

Link: CVE-2019-16785

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2019-12-20T23:15:11.167

Modified: 2024-11-21T04:31:11.193

Link: CVE-2019-16785

cve-icon Redhat

Severity : Important

Publid Date: 2019-12-20T00:00:00Z

Links: CVE-2019-16785 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses