High 8.7Published Mar 11, 2026

CVE-2026-31958Tornado has a DoS due to too many multipart parts

Updated under an hour ago (Oct 27, 2026, 3:00 AM ET)

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It affects tornadoweb tornado. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for tornadoweb tornado

Exploited in the last 30 days

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: 8.7 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weakness (CWE): CWE-400
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Modified
Record last updated: Apr 1, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

tornadoweb tornado tornadoweb:tornado (from the name)	before 6.5.5	CNA record
tornadoweb tornado tornadoweb:tornado	before 6.5.5	NVD

References

References

https://github.com/tornadoweb/tornado/security/advisories/GHSA-qjxf-f2mg-c6mc	x-refsource-confirm, vendor-advisory
https://lists.debian.org/debian-lts-announce/2026/04/msg00000.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.