CVE-2019-16785

HTTP Request Smuggling: LF vs CRLF handling in Waitress

Published Dec 20, 2019 CVSS 3.1 · 7.1 High EPSS 2.5% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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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
History

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