CVE-2026-31958

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.

PUBLISHED Reserved 2026-03-10 | Published 2026-03-11 | Updated 2026-03-12 | Assigner GitHub_M

Problem types

CWE-400: Uncontrolled Resource Consumption

Product status

References

github.com/...ornado/security/advisories/GHSA-qjxf-f2mg-c6mc

cve.org (CVE-2026-31958)

nvd.nist.gov (CVE-2026-31958)

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