Skip to content
CVE PROGRAM SOURCE RECORD8.7 High

CVE-2026-31958

Tornado has a DoS due to too many multipart parts

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

tornadoweb tornado

  • < 6.5.5affected

References