CVE-2026-82397 Tornado: Urlencoded body parsing omits max_num_fields, so one request can stall the event loop

Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.8, Tornado parses application/x-www-form-urlencoded request bodies with urllib.parse.parseqs in tornado/escape.py without passing maxnumfields. RequestHandler.execute in tornado/web.py parses the body before handl...