CVE-2019-16786

HTTP Request Smuggling: Invalid Transfer-Encoding in Waitress

Description

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.

Category

7.1
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.52%
Vendor Advisory fedoraproject.org Vendor Advisory fedoraproject.org Vendor Advisory redhat.com Vendor Advisory pylonsproject.org
Affected: Pylons Waitress
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2019-16786?
CVE-2019-16786 has been scored as a high severity vulnerability.
How to fix CVE-2019-16786?
To fix CVE-2019-16786, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2019-16786 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2019-16786 is being actively exploited. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2019-16786?
CVE-2019-16786 affects Pylons Waitress.
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