# PYSEC-2020-197 - Waitress through version 1.3.1 allows request smuggling by sending the Content-Length header twice…

Source: https://junglewise.ai/threats/pysec-2020-197-waitress-through-version-1-3-1-allows-request-smuggling-9f6e1628  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2020-01-22  
License: CC BY 4.0 with a link back

Severity: info · Published 2020-01-22

Waitress through version 1.3.1 allows request smuggling by sending the Content-Length header twice. Waitress would header fold a double Content-Length header and due to being unable to cast the now comma separated value to an integer would set the Content-Length to 0 internally. If two Content-Length headers are sent in a single request, Waitress would treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining. This issue is fixed in Waitress 1.4.0.

Technologies: [waitress (PyPI)](https://junglewise.ai/threats/technologies/waitress). Vendors: [PyPI](https://junglewise.ai/threats/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 22 January 2020.

**Which products and versions are affected?** waitress (PyPI) GIT:introduced=0,fixed=575994cd42e83fd772a5f7ec98b2c56751bd3f65|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

  ```sh
  pip install "waitress>=1.4.0"
  ```


## Affected products

- waitress (PyPI) GIT:introduced=0,fixed=575994cd42e83fd772a5f7ec98b2c56751bd3f65|ECOSYSTEM:introduced=0,fixed=1.4.0

## Related threats

- [Waitress denial of service via unclean socket handling](https://junglewise.ai/threats/cve-2024-49769-waitress-denial-of-service-via-unclean-socket-handling)
- [Waitress has request processing race condition in HTTP pipelining with invalid first request](https://junglewise.ai/threats/cve-2024-49768-waitress-has-request-processing-race-condition-in-http-pipelining)
- [Uncaught Exception (due to a data race) leads to process termination in Waitress](https://junglewise.ai/threats/cve-2022-31015-uncaught-exception-due-to-a-data-race-leads-to-process)
- [HTTP Request Smuggling in waitress](https://junglewise.ai/threats/cve-2022-24761-http-request-smuggling-in-waitress)
- [Catastrophic backtracking in regex allows Denial of Service in Waitress](https://junglewise.ai/threats/cve-2020-5236-catastrophic-backtracking-in-regex-allows-denial-of-service-in)