CVE-2019-16786

Summary

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.

Affected Software

VendorProductVersion RangeStatus
PylonsWaitress<= 1.3.1 <= 1.3.1affected

Weaknesses

  • CWE-444: CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')

ADP Enrichment

CVE Program Container

Additional References

References