Waitress through version 1.3.1 implemented a "MAY" part of the RFC7230 which states: "Although the line terminator for the start-line and header fields is the sequence CRLF, a recipient MAY recognize a single LF as a line terminator and ignore any preceding CR." Unfortunately if a front-end server does not parse header fields with an LF the same way as it does those with a CRLF it can lead to the front-end and the back-end server parsing the same HTTP message in two different ways. This can lead to a potential for HTTP request smuggling/splitting whereby Waitress may see two requests while the front-end server only sees a single HTTP message. This issue is fixed in Waitress 1.4.0.
CVSS Details
- CVSS 3.1 Base Score: 7.1
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | alpine-linux-upgrade-py3-waitress | Mar 24, 2020 | Dec 20, 2019 | |
| Debian | debian-upgrade-waitress | May 16, 2022 | Dec 20, 2019 | |
| Huawei Euleros 2_0_sp8 | huawei-euleros-2_0_sp8-upgrade-python2-waitress | Aug 31, 2020 | Dec 20, 2019 | |
| Oracle Solaris | oracle-solaris-11-4-upgrade-legacy-library-python-waitress-34-1-4-3-11-4-21-0-1-69-0oracle-solaris-11-4-upgrade-legacy-library-python-waitress-35-1-4-3-11-4-21-0-1-69-0oracle-solaris-11-4-upgrade-library-python-2-waitress-0-8-5-11-4-0-0-1-9-0oracle-solaris-11-4-upgrade-library-python-2-waitress-26-0-8-5-11-4-0-0-1-9-0oracle-solaris-11-4-upgrade-library-python-2-waitress-27-0-8-5-11-4-0-0-1-9-0oracle-solaris-11-4-upgrade-library-python-waitress-1-4-3-11-4-21-0-1-69-0oracle-solaris-11-4-upgrade-library-python-waitress-26-0-8-5-11-4-0-0-1-9-0oracle-solaris-11-4-upgrade-library-python-waitress-27-1-4-3-11-4-21-0-1-69-0oracle-solaris-11-4-upgrade-library-python-waitress-34-1-4-3-11-4-21-0-1-69-0oracle-solaris-11-4-upgrade-library-python-waitress-35-1-4-3-11-4-21-0-1-69-0 | Jan 19, 2021 | Dec 20, 2019 | |
| Suse | — | suse-upgrade-python2-waitresssuse-upgrade-python3-waitress | Nov 11, 2020 | Dec 20, 2019 |
| Ubuntu | no-fix-ubuntu-package | Jun 26, 2025 | Dec 20, 2019 |
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