PYSEC-2019-66 - Waitress through version 1.3.1 implemented a "MAY" part of the RFC7230 which states: "Although the…

Severity: info · Published 2019-12-20

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.

Technologies: waitress (PyPI). Vendors: PyPI.

Quick answers

Is This vulnerability exploited in the wild?
No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
How severe is This vulnerability?
Informational severity, published 20 December 2019.
Which products and versions are affected?
waitress (PyPI) GIT:introduced=0,fixed=8eba394ad75deaf9e5cd15b78a3d16b12e6b0eba|ECOSYSTEM:introduced=0,fixed=1.4.0.
Is there a fix for This vulnerability?
Yes. waitress (PyPI): upgrade to 1.4.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected?
Check whether you run waitress (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • waitress (PyPI): upgrade to 1.4.0 or later
    pip install "waitress>=1.4.0"

Affected products

  • waitress (PyPI) GIT:introduced=0,fixed=8eba394ad75deaf9e5cd15b78a3d16b12e6b0eba|ECOSYSTEM:introduced=0,fixed=1.4.0

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