VULNERABILITY INTELLIGENCE

CVE-2026-31958

CVSS score7.5 HIGH
EPSS probability0.39%
CISA KEVNot currently listed
Published2026-03-11
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Description

Tornado is a Python web framework and asynchronous networking library. In versions of Tornado prior to 6.5.5, the only limit on the number of parts in multipart/form-data is the max_body_size setting (default 100MB). Since parsing occurs synchronously on the main thread, this creates the possibility of denial-of-service due to the cost of parsing very large multipart bodies with many parts. This vulnerability is fixed in 6.5.5.

Weakness classification

  • security-advisories@github.com: CWE-400

Primary references