https://vulnerability.circl.lu/rss/recent/all/10 Most recent entries from all 2026-09-29T06:21:27.669409+00:00 Vulnerability-Lookup info@circl.lu python-feedgen Contains only the most 10 recent entries. https://vulnerability.circl.lu/vuln/cve-2019-16789 CVE-2019-16789 — HTTP Request Smuggling in Waitress: Invalid whitespace characters in headers 2026-09-29T06:21:27.717427+00:00

Affected: Pylons Waitress

In Waitress through version 1.4.0, if a proxy server is used in front of waitress, an invalid request may be sent by an attacker that bypasses the front-end and is parsed differently by waitress leading to a potential for HTTP request smuggling. Specially crafted requests containing special whitespace characters in the Transfer-Encoding header would get parsed by Waitress as being a chunked request, but a front-end server would use the Content-Length instead as the Transfer-Encoding header is considered invalid due to containing invalid characters. If a front-end server does HTTP pipelining to a backend Waitress server this could lead to HTTP request splitting which may lead to potential cache poisoning or unexpected information disclosure. This issue is fixed in Waitress 1.4.1 through more strict HTTP field validation.

 https://vulnerability.circl.lu/vuln/ghsa-968f-66r5-5v74 GHSA-968f-66r5-5v74 — HTTP Request Smuggling in Waitress: Invalid whitespace characters in headers (Follow-up) 2026-09-29T06:21:27.717587+00:00

Affected: PyPI: waitress

### Impact

The patches introduced to fix https://github.com/Pylons/waitress/security/advisories/GHSA-m5ff-3wj3-8ph4 were not complete and still would allow an attacker to smuggle requests/split a HTTP request with invalid data.

This updates the existing CVE with ID: CVE-2019-16789

### Patches

Waitress version 1.4.2 has been updated to now validate HTTP headers better to avoid the issue, completely fixing all known issues with whitespace.

### Workarounds

There are no work-arounds, upgrading to Waitress 1.4.2 is highly recommended.

### References

See https://github.com/Pylons/waitress/security/advisories/GHSA-m5ff-3wj3-8ph4 for more information on the security issue.

### For more information

If you have any questions or comments about this advisory:

* open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related) * email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)

 https://vulnerability.circl.lu/vuln/pysec-2019-138 PYSEC-2019-138 2026-09-29T06:21:27.717664+00:00

Affected: PyPI: waitress

In Waitress through version 1.4.0, if a proxy server is used in front of waitress, an invalid request may be sent by an attacker that bypasses the front-end and is parsed differently by waitress leading to a potential for HTTP request smuggling. Specially crafted requests containing special whitespace characters in the Transfer-Encoding header would get parsed by Waitress as being a chunked request, but a front-end server would use the Content-Length instead as the Transfer-Encoding header is considered invalid due to containing invalid characters. If a front-end server does HTTP pipelining to a backend Waitress server this could lead to HTTP request splitting which may lead to potential cache poisoning or unexpected information disclosure. This issue is fixed in Waitress 1.4.1 through more strict HTTP field validation.