RHSA-2026:85135

A vulnerability was discovered in Tornado where it improperly handles HTTP requests containing duplicate Transfer-Encoding: chunked headers. When duplicate Transfer-Encoding headers are present in an incoming request, Tornado ignores them and treats the request as body-less, leaving the chunked message body unparsed in the HTTP socket stream. When Tornado is deployed behind a reverse proxy or load balancer that correctly processes chunked payloads, an unauthenticated remote attacker can exploit this parsing discrepancy to conduct HTTP request smuggling, bypass proxy security restrictions, poison intermediate caches, or desynchronize backend connections.