Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') in tornado

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS

• CVE-2024-14029: 0.36% estimated exploitation activity in the next 30 days; percentile 29.98 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary When Tornado receives a request with two Transfer-Encoding: chunked headers, it ignores them both. This enables request smuggling when Tornado is deployed behind a proxy server that emits such requests. Pound) does this. PoC 0. Install Tornado. 1. Start a simple Tornado server that echoes each received request's body: 2. Send a valid chunked request: 3. Observe that the response is as expected: 4. Send a request with two Transfer-Encoding: chunked headers: 5. Observe the strange response: This is because Tornado believes that the request has no message body, so it tries to interpret 1\r\nZ\r\n0\r\n\r\n as its own request, which causes a 400 response. With a little cleverness involving chunk-exts, you can get Tornado to instead respond 405, which has the potential to desynchronize the connection, as opposed to 400 which should always result in a connection closure. Impact Anyone using Tornado behind a proxy that forwards requests containing multiple Transfer-Encoding: chunked…

Published by the source

6 Jun 2024, 21:41 UTC

Last modified by the source

16 Sep 2026, 03:56 UTC

Source last checked

26 Oct 2026, 13:16 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-753j-mpmx-qq6g

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-753j-mpmx-qq6g

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# Patch Next advisory brief: CVE-2024-14029

Advisory: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') in tornado
IDs: CVE-2024-14029, GHSA-753j-mpmx-qq6g
Record: https://patchnext.com/advisories/cve-2024-14029 (revision 2, source checked 26 Oct 2026, 13:16 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: tornado 6.4.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI tornado: affected <= 6.4.0; fixed in 6.4.1

## Suggested inspection (read-only)
- `python -m pip show tornado`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on tornado.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-753j-mpmx-qq6g (OSV record GHSA-753j-mpmx-qq6g lists affected ranges: PyPI tornado >=0 <6.4.1 (fixed))
- Verified: https://github.com/advisories/GHSA-753j-mpmx-qq6g (GitHub-reviewed advisory GHSA-753j-mpmx-qq6g lists affected ranges: PyPI tornado >=0 <=6.4.0)

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