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CVE-2025-47287

CVE-2025-47287 · Tornado vulnerable to excessive logging caused by malformed multipart form data

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 7.5 · High · EPSS 0.7% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • tornado

    Versions
    • < 6.5.0: Affected

    No fix published

  • python-tornado Debian:12

    Versions
    • 6.2.0-3
    • 6.2.0-3+deb12u1
    Affected ranges
    • ECOSYSTEM: < 6.2.0-3+deb12u2

    Update to 6.2.0-3+deb12u2

  • python-tornado Debian:13

    Affected ranges
    • ECOSYSTEM: < 6.4.2-2

    Update to 6.4.2-2

  • python-tornado Debian:14

    Affected ranges
    • ECOSYSTEM: < 6.4.2-2

    Update to 6.4.2-2

  • tornado PyPI

    Versions
    • 0.2
    • 1.0
    • 1.1
    • 1.1.1
    • 1.2
    • 1.2.1
    • 2.0
    • 2.1
    • 2.1.1
    • 2.2
    • 2.2.1
    • 2.3
    • 2.4
    • 2.4.1
    • 3.0
    • 3.0.1
    • 3.0.2
    • 3.1
    • 3.1.1
    • 3.2
    • 3.2.1
    • 3.2.2
    • 4.0
    • 4.0.1
    • 4.0.2
    • 4.1
    • 4.1b2
    • 4.2
    • 4.2.1
    • 4.2b1
    • 4.3
    • 4.3b1
    • 4.3b2
    • 4.4
    • 4.4.1
    • 4.4.2
    • 4.4.3
    • 4.4b1
    • 4.5
    • 4.5.1
    • 4.5.2
    • 4.5.3
    • 4.5b1
    • 4.5b2
    • 5.0
    • 5.0.1
    • 5.0.2
    • 5.0a1
    • 5.0b1
    • 5.1
    • 5.1.1
    • 5.1b1
    • 6.0
    • 6.0.1
    • 6.0.2
    • 6.0.3
    • 6.0.4
    • 6.0a1
    • 6.0b1
    • 6.1
    • 6.1b1
    • 6.1b2
    • 6.2
    • 6.2b1
    • 6.2b2
    • 6.3
    • 6.3.1
    • 6.3.2
    • 6.3.3
    • 6.3b1
    • 6.4
    • 6.4.1
    • 6.4.2
    • 6.4b1
    • 6.5b1
    Affected ranges
    • ECOSYSTEM: < 6.5

    Update to 6.5

  • python-tornado Ubuntu:Pro:16.04:LTS

    Versions
    • 4.2.1-1ubuntu2
    • 4.2.1-1ubuntu3
    • 4.2.1-1ubuntu3.1
    • 4.2.1-1ubuntu3.1+esm1
    • 4.2.1-1ubuntu3.1+esm2
    • 4.2.1-1ubuntu3.1+esm3
    • 4.2.1-1ubuntu3.1+esm4
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-tornado Ubuntu:Pro:18.04:LTS

    Versions
    • 4.5.1-2.1~build2
    • 4.5.2-1
    • 4.5.3-1
    • 4.5.3-1ubuntu0.1
    • 4.5.3-1ubuntu0.2
    • 4.5.3-1ubuntu0.2+esm1
    • 4.5.3-1ubuntu0.2+esm2
    • 4.5.3-1ubuntu0.2+esm3
    • 4.5.3-1ubuntu0.2+esm4
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-tornado Ubuntu:Pro:20.04:LTS

    Versions
    • 5.1.1-4ubuntu1
    • 5.1.1-4ubuntu5
    • 6.0.3+really5.1.1-2
    • 6.0.3+really5.1.1-2build1
    • 6.0.3+really5.1.1-2build2
    • 6.0.3+really5.1.1-3
    • 6.0.3+really5.1.1-3ubuntu0.1~esm1
    • 6.0.3+really5.1.1-3ubuntu0.1~esm3
    • 6.0.3+really5.1.1-3ubuntu0.1~esm5
    • 6.0.3+really5.1.1-3ubuntu0.1~esm7
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-tornado Ubuntu:Pro:22.04:LTS

    Versions
    • 6.1.0-1build1
    • 6.1.0-2
    • 6.1.0-3
    • 6.1.0-3build1
    • 6.1.0-3ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: < 6.1.0-3ubuntu0.1~esm2

    Update to 6.1.0-3ubuntu0.1~esm2

  • python-tornado Ubuntu:24.04:LTS

    Versions
    • 6.3.2-1
    • 6.4.0-0ubuntu1
    • 6.4.0-1
    • 6.4.0-1build1
    • 6.4.0-1ubuntu0.1
    Affected ranges
    • ECOSYSTEM: < 6.4.0-1ubuntu0.2

    Update to 6.4.0-1ubuntu0.2

  • python-tornado Ubuntu:25.10

    Versions
    • 6.4.2-1
    Affected ranges
    • ECOSYSTEM: < 6.4.2-2

    Update to 6.4.2-2

Original sources

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