CVE-2026-91990 [HIGH] – Tornado before 6.5.8 contains a memory amplification vulnerability in parse_multipart_form

Tornado before 6.5.8 contains a memory amplification vulnerability in parse_multipart_form_data that splits multipart data before validating the max_parts limit. Attackers can send crafted multipart requests with many parts to create large transient lists, exhausting server memory and causing denial of service.