Hi,

The following vulnerability was published for python-tornado.

CVE-2026-82397[0]:
| Tornado is a Python web framework and asynchronous networking
| library. Prior to 6.5.8, Tornado parses application/x-www-form-
| urlencoded request bodies with urllib.parse.parse_qs in
| tornado/escape.py without passing max_num_fields.
| RequestHandler._execute in tornado/web.py parses the body before
| handler dispatch through HTTPServerRequest._parse_body and
| parse_body_arguments in tornado/httputil.py, so an unauthenticated
| request body containing millions of separator-delimited fields can
| synchronously stall the single-threaded event loop and delay every
| connection. The body is bounded only by max_buffer_size, which
| defaults to 104857600 bytes. This issue is fixed in version 6.5.8.


If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities & Exposures) id in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2026-82397
https://www.cve.org/CVERecord?id=CVE-2026-82397
[1] https://github.com/tornadoweb/tornado/security/advisories/GHSA-mpf4-983q-p7j4
[2] https://github.com/tornadoweb/tornado/commit/8d6363ed7b69d5f0da806efe34d256627a2191de

Please adjust the affected versions in the BTS as needed.

Regards,
Salvatore