CVE-2026-103261 Tornado before 6.5.9 Denial of Service via Query String

Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.init, allowing remote attackers to cause event-loop stalling by sending requests with thousands of query parameters. Attackers can send unauthenticated GET requests with unbounded query-string field counts ...

CVE-2026-103261

The Tornado web framework versions prior to 6.5.9 are vulnerable to a Denial of Service (DoS) condition. The root cause is a lack of limits on the number of query string fields processed within the HTTPServerRequest.__init__ component. A remote, unauthenticated attacker can exploit this by sendin...