Debian: DLA-4188-1 critical: python-tornado DoS risk report

CVE-2025-47287

When Tornado's 'multipart/form-data' parser encounters certain
errors, it logs a warning but continues trying to parse the
remainder of the data. This allows remote attackers to generate an
extremely high volume of logs, constituting a DoS attack. This DoS
is compounded by the fact that the logging subsystem is synchronous.

For Debian 11 bullseye, this problem has been fixed in version
6.1.0-1+deb11u2.

We recommend that you upgrade your python-tornado packages.

For the detailed security status of python-tornado please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/source-package/python-tornado

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS