HIGH7.5

PYSEC-2026-1433

Gunicorn HTTP Request/Response Smuggling vulnerability

Quick fix

PYSEC-2026-1433 — gunicorn: upgrade to the fixed version with the command below.

pip install --upgrade 'gunicorn>=22.0.0'

Details

Gunicorn version 21.2.0 does not properly validate the value of the 'Transfer-Encoding' header as specified in the RFC standards, which leads to the default fallback method of 'Content-Length,' making it vulnerable to TE.CL request smuggling. This vulnerability can lead to cache poisoning, data exposure, session manipulation, SSRF, XSS, DoS, data integrity compromise, security bypass, information leakage, and business logic abuse.

Are you affected?

Enter the version of the package you're using.

Affected packages

PyPI/gunicorn

Introduced in: 0Fixed in: 22.0.0

Fixpip install --upgrade 'gunicorn>=22.0.0'

References

https://nvd.nist.gov/vuln/detail/CVE-2024-6827[ADVISORY]
https://github.com/benoitc/gunicorn/issues/3087[WEB]
https://github.com/benoitc/gunicorn/issues/3278[WEB]
https://github.com/benoitc/gunicorn/pull/3113[WEB]
https://github.com/benoitc/gunicorn[PACKAGE]
https://github.com/benoitc/gunicorn/releases/tag/22.0.0[WEB]
https://huntr.com/bounties/1b4f8f38-39da-44b6-9f98-f618639d0dd7[WEB]
https://pypi.org/project/gunicorn[PACKAGE]
https://github.com/advisories/GHSA-hc5x-x2vx-497g[ADVISORY]