Vulnerability in Agendaless Waitress
CVE-2019-16786
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.
Vulnerability class: HTTP Request Smuggling
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.024 (83.2th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 83rd percentile — 83.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.024 · newest: 0.024 · change: 0.000
Affected products
- Agendaless Waitress
- Oracle Communications Cloud Native Core Network Function Environment — versions 1.10.0
- Pylons Waitress — versions <= 1.3.1
- Debian Linux — versions 9.0
- Fedoraproject Fedora — versions 30, 31
- Red Hat OpenStack — versions 15
Weakness classification (CWE)
Public proof-of-concept exploits
References
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- access.redhat.com/errata/RHSA-2020:0720 (vendor-advisory, Third Party Advisory)
- www.oracle.com/security-alerts/cpuapr2022.html (Patch, Third Party Advisory)
- docs.pylonsproject.org/projects/waitress/en/latest/ (Release Notes, Vendor Advisory)
- github.com/Pylons/waitress/security/advisories/GHSA-g2xc-35jw-c63p (Third Party Advisory)
- github.com/Pylons/waitress/commit/f11093a6b3240fc26830b6111e826128af7771c3 (Patch, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2022/05/msg00011.html (mailing-list, Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2019-16786?
- CVE-2019-16786 is a high-severity vulnerability in Agendaless Waitress, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 7.1/10. Published 2019-12-20.
- How severe is CVE-2019-16786?
- High severity. CVSS v3 base score is 7.1 out of 10.
- Is CVE-2019-16786 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.