CVE-2019-16786

Aliases:GHSA-g2xc-35jw-c63pPYSEC-2019-137
Advisory lineage Upstream: 0 Downstream: 12
Modified
Published: 20 Dec 2019, 23:00
Last modified:05 Aug 2024, 01:24

Vulnerability Summary

Overall Risk (default)
medium
30/100
CVSS Score
7.5 HIGH
v3.1 (nvd)
EPSS Score
0.8% LOW
1% probability -0.10%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

20 Dec 2019, 23:00
Published
Vulnerability first disclosed
05 Aug 2024, 01:24
Last Modified
Vulnerability information updated

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.

CVSS Metrics

  • v4.0•MEDIUM•Score: 5.1CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N
  • v3.1•HIGH•Score: 7.1CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N
  • v3.1•HIGH•Score: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
  • v2.0•MEDIUM•Score: 5AV:N/AC:L/Au:N/C:N/I:P/A:N

EPSS Trends

Current EPSS score: 0.80%• Percentile: 74%

Techniques & Countermeasures

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

    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.

Affected Systems

  • agendaless•waitress

    < 1.3.1

  • debian•debian_linux

    9.0

  • fedoraproject•fedora

    30 | 31

  • oracle•communications_cloud_native_core_network_function_cloud_native_environment

    1.10.0

  • pylons•waitress

    ≥ <= 1.3.1, ≤ 1.3.1

  • PyPI•waitress

    < f11093a6b3240fc26830b6111e826128af7771c3 | < 1.3.1 | < 1.4.0

  • redhat•openstack

    15

References (15)