CVE-2025-47287

Tornado vulnerable to excessive logging caused by malformed multipart form data

Published May 15, 2025 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4188-1 python-tornado security update
Debian DSA Debian DSA DSA-5938-1 python-tornado security update
EUVD EUVD EUVD-2025-15444 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.
Github GHSA Github GHSA GHSA-7cx3-6m66-7c5m Tornado vulnerable to excessive logging caused by malformed multipart form data
Ubuntu USN Ubuntu USN USN-7547-1 Tornado vulnerability
History
Type Values Removed Values Added
First Time appeared Debian
Debian debian Linux
Tornadoweb
Tornadoweb tornado
CPEs cpe:2.3:a:tornadoweb:tornado:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
Vendors & Products Debian
Debian debian Linux
Tornadoweb
Tornadoweb tornado
Type Values Removed Values Added
First Time appeared Redhat rhel Els
CPEs cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel Els
Type Values Removed Values Added
CPEs cpe:/a:redhat:rhel_e4s:8.4::highavailability
cpe:/a:redhat:rhel_tus:8.4::highavailability
Type Values Removed Values Added
First Time appeared Redhat rhel E4s
Redhat rhel Tus
CPEs cpe:/a:redhat:rhel_e4s:8.6::highavailability
cpe:/a:redhat:rhel_e4s:9.0::highavailability
cpe:/a:redhat:rhel_eus:8.8::highavailability
cpe:/a:redhat:rhel_tus:8.6::highavailability
Vendors & Products Redhat rhel E4s
Redhat rhel Tus
Type Values Removed Values Added
CPEs cpe:/a:redhat:enterprise_linux:8::highavailability
Type Values Removed Values Added
First Time appeared Redhat rhel Eus
CPEs cpe:/a:redhat:rhel_eus:9.2
cpe:/a:redhat:rhel_eus:9.4
Vendors & Products Redhat rhel Eus
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10.0
Type Values Removed Values Added
First Time appeared Redhat
Redhat enterprise Linux
CPEs cpe:/a:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Tornado vulnerable to excessive logging caused by malformed multipart form data
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 29, 2025, 6:04 AM
Reserved
May 5, 2025, 4:53 PM
Status
Analyzed
Published
May 15, 2025, 10:15 PM
Modified
Jun 17, 2026, 9:27 AM
Severity
Important
Public date
May 15, 2025, 9:17 PM