CVE-2025-47287

Tornado vulnerable to excessive logging caused by malformed multipart form data

State
Published
Severity
7.5 High
Published
May 15, 2025
Updated
May 29, 2025
Reserved
May 5, 2025

Read the record on cve.org

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

CVSSScoreVectorSource
3.17.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HGitHub_M

Weaknesses

  • CWE-770 Allocation of Resources Without Limits or Throttling

Affected Products

ProductVersions
tornadotornadoweb
  • < 6.5.0Affected

References

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