Vulnerability · Published Mar 17, 2022 · Assigned by GitHub_M
CVE-2022-24761HTTP Request Smuggling in waitress
High 7.5
In plain English
A high-severity security flaw in waitress from Pylons. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.8% (higher than 78% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Waitress is a Web Server Gateway Interface server for Python 2 and 3. When using Waitress versions 2.1.0 and prior behind a proxy that does not properly validate the incoming HTTP request matches the RFC7230 standard, Waitress and the frontend proxy may disagree on where one request starts and where it ends. This would allow requests to be smuggled via the front-end proxy to waitress and later behavior. There are two classes of vulnerability that may lead to request smuggling that are addressed by this advisory: The use of Python's `int()` to parse strings into integers, leading to `+10` to be parsed as `10`, or `0x01` to be parsed as `1`, where as the standard specifies that the string should contain only digits or hex digits; and Waitress does not support chunk extensions, however it was discarding them without validating that they did not contain illegal characters. This vulnerability has been patched in Waitress 2.1.1. A workaround is available. When deploying a proxy in front of waitress, turning on any and all functionality to make sure that the request matches the RFC7230 standard. Certain proxy servers may not have this functionality though and users are encouraged to upgrade to the latest version of waitress instead.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | waitress | 2.1.1-1 | DEBIAN-CVE-2022-24761 |
| Debian:13 | waitress | 2.1.1-1 | DEBIAN-CVE-2022-24761 |
| Debian:14 | waitress | 2.1.1-1 | DEBIAN-CVE-2022-24761 |
| PyPI | waitress | 2.1.1 | GHSA-4f7p-27jc-3c36 |
| PyPI | waitress | 2.1.1 | PYSEC-2022-169 |
| Ubuntu:22.04:LTS | waitress | 1.4.4-1.1ubuntu1 | UBUNTU-CVE-2022-24761 |
Affected products (as reported)
Weakness: CWE-444 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
References
- https://github.com/Pylons/waitress/security/advisories/GHSA-4f7p-27jc-3c36 x_refsource_CONFIRM
- https://github.com/Pylons/waitress/commit/9e0b8c801e4d505c2ffc91b891af4ba48af715e0 x_refsource_MISC
- https://github.com/Pylons/waitress/releases/tag/v2.1.1 x_refsource_MISC
- [debian-lts-announce] 20220512 [SECURITY] [DLA 3000-1] waitress security update mailing-list, x_refsource_MLIST
- DSA-5138 vendor-advisory, x_refsource_DEBIAN