CVE-2022-24761
This would allow requests to be smuggled via the front-end proxy to waitress and later behavior.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.78%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- EPSS
- 1.78% probability · 77th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-444
- Affected
- agendaless/waitress · debian/debian linux
- Source
- security-advisories@github.com
References
- https://github.com/Pylons/waitress/commit/9e0b8c801e4d505c2ffc91b891af4ba48af715e0Patch, Release Notes, Third Party Advisory
- https://github.com/Pylons/waitress/releases/tag/v2.1.1Release Notes, Third Party Advisory
- https://github.com/Pylons/waitress/security/advisories/GHSA-4f7p-27jc-3c36Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/05/msg00011.htmlMailing List, Third Party Advisory
- https://www.debian.org/security/2022/dsa-5138Third Party Advisory
- https://github.com/Pylons/waitress/commit/9e0b8c801e4d505c2ffc91b891af4ba48af715e0Patch, Release Notes, Third Party Advisory
- https://github.com/Pylons/waitress/releases/tag/v2.1.1Release Notes, Third Party Advisory
- https://github.com/Pylons/waitress/security/advisories/GHSA-4f7p-27jc-3c36Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/05/msg00011.htmlMailing List, Third Party Advisory
- https://www.debian.org/security/2022/dsa-5138Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.