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CVE PROGRAM SOURCE RECORD7.1 High

CVE-2019-16785

HTTP Request Smuggling: LF vs CRLF handling in Waitress

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Status
Published
Published
Updated
Assigning organization
GitHub_M

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Pylons Waitress

  • <= 1.3.1 to ≤ 1.3.1affected

References