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Moderate severityNVD Advisory· Published Dec 20, 2019· Updated Aug 5, 2024

HTTP Request Smuggling: LF vs CRLF handling in Waitress

CVE-2019-16785

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.

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Affected packages

Versions sourced from the GitHub Security Advisory.

PackageAffected versionsPatched versions
waitressPyPI
< 1.4.01.4.0

Affected products

309

Patches

Vulnerability mechanics

References

13

News mentions

0

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