CVE-2025-47287

HIGH

Tornado < 6.5.0 - Denial of Service via Multipart Form Data Parser

Title source: llm
STIX 2.1

Description

Tornado is a Python web framework and asynchronous networking library. 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. All versions of Tornado prior to 6.5.0 are affected. The vulnerable parser is enabled by default. Upgrade to Tornado version 6.50 to receive a patch. As a workaround, risk can be mitigated by blocking `Content-Type: multipart/form-data` in a proxy.

Scores

CVSS v3 7.5
EPSS 0.0064
EPSS Percentile 45.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-770
Status published
Products (3)
debian/debian_linux 11.0
pypi/tornado 0 - 6.5PyPI
tornadoweb/tornado < 6.5.0
Published May 15, 2025
Tracked Since Feb 18, 2026