CVE-2019-16786
HTTP Request Smuggling: Invalid Transfer-Encoding in Waitress
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High7.1 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
- EPSS (exploitation in 30 days)
- 2.4% · top 16% of all CVEs (5 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.1.
Weakness
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIwaitressGHSA-g2xc-35jw-c63p (opens in a new tab)
References (8)
- FEDORA-2020-bdcc8ffc24 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- FEDORA-2020-65a7744e38 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- RHSA-2020:0720 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- https://www.oracle.com/security-alerts/cpuapr2022.html (opens in a new tab)x_refsource_MISCx_transferred
- https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/Pylons/waitress/security/advisories/GHSA-g2xc-35jw-c63p (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/Pylons/waitress/commit/f11093a6b3240fc26830b6111e826128af7771c3 (opens in a new tab)x_refsource_MISCx_transferred
- [debian-lts-announce] 20220512 [SECURITY] [DLA 3000-1] waitress security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-g2xc-35jw-c63p (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2019-16786)Record last updated .