Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Tornadoweb | Tornado | < 6.5.5 |
Related Weaknesses (CWE)
References
- https://github.com/tornadoweb/tornado/security/advisories/GHSA-qjxf-f2mg-c6mcVendor Advisory
- https://lists.debian.org/debian-lts-announce/2026/04/msg00000.html
FAQ
What is CVE-2026-31958?
CVE-2026-31958 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 ...
How severe is CVE-2026-31958?
CVE-2026-31958 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-31958?
Check the references section above for vendor advisories and patch information. Affected products include: Tornadoweb Tornado.