Resource exhaustion in Tornado - CVE-2026-31958
Published: April 27, 2026
Vulnerability identifier: #VU128147
CSH Severity: Medium
CVSSv4.0: 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/E:U/U:Green
CVE-ID: CVE-2026-31958
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
Tornado
Tornado
Software vendor:
Tornado
Tornado
Description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource consumption in multipart/form-data parsing on the main thread when processing very large multipart request bodies with many parts. A remote attacker can send a specially crafted multipart/form-data request to cause a denial of service.
The number of multipart parts is limited only by the max_body_size setting.
Remediation
Install security update from vendor's website.