Waitress up to 1.3.1 HTTP Header Transfer-Encoding request smuggling

Summaryinfo

A vulnerability has been found in Waitress up to 1.3.1 and classified as critical. Affected by this issue is some unknown functionality of the component HTTP Header Handler. This manipulation of the argument Transfer-Encoding causes request smuggling. This vulnerability is tracked as CVE-2019-16786. The attack is possible to be carried out remotely. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability has been found in Waitress up to 1.3.1 and classified as critical. Affected by this vulnerability is an unknown part of the component HTTP Header Handler. The manipulation of the argument Transfer-Encoding with an unknown input leads to a request smuggling vulnerability. The CWE definition for the vulnerability is CWE-444. The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Waitress through version 1.3.1 would parse the Transfer-Encoding header and only look for a single string value, if that value was not chunked it would fall through and use the Content-Length header instead. According to the HTTP standard Transfer-Encoding should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with chunked. Requests sent with: "Transfer-Encoding: gzip, chunked" would incorrectly get ignored, and the request would use a Content-Length header instead to determine the body size of the HTTP message. This could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining. This issue is fixed in Waitress 1.4.0.

The weakness was disclosed 12/20/2019 (GitHub Repository). The advisory is shared at github.com. This vulnerability is known as CVE-2019-16786 since 09/24/2019. The exploitation appears to be difficult. The attack can be launched remotely. A single authentication is necessary for exploitation. Technical details are known, but no exploit is available.

Upgrading to version 1.4.0 eliminates this vulnerability.

The entry VDB-147576 is pretty similar. Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

• Waitress

Version

• 1.3.0
• 1.3.1

License

• open-source

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CPE 2.2info

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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