{"id":"GO-2026-6603","revision":"0755da5a7b7c4f26858cea72dbc3172d","records":[{"revision":"0755da5a7b7c4f26858cea72dbc3172d","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GO-2026-6603","aliases":["BIT-golang-2026-78659","CVE-2026-78659"],"title":"HTTP/2 server memory exhaustion due to Trailer headers in net/http","description":"When \"Trailer\" headers are sent by a client, the HTTP server internally uses the header values to populate the Request.Trailer map passed to the server handler. Because Request.Trailer is a map, each entry incurs memory overhead. For HTTP/2 servers, a malicious client can exploit this by sending a \"Trailer\" header that declares a large number of fields, causing the server to allocate a disproportionate amount of memory while bypassing Server.MaxHeaderValueCount and Server.MaxHeaderBytes limits. This exploit is not applicable for HTTP/1 servers, which do not support multiplexing a large number of requests over one TCP connection, and whose Server.MaxHeaderBytes are calculated differently.","state":0,"publishedAt":"2026-10-08T22:31:09+00:00","modifiedAt":"2026-10-16T09:55:47.0681174+00:00","affected":[{"ecosystem":"Go","name":"stdlib","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"1.26.9"}]}],"versions":[],"rawVersionEvidence":null},{"ecosystem":"Go","name":"stdlib","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"1.27.0-0"},{"kind":"fixed","version":"1.27.2"}]}],"versions":[],"rawVersionEvidence":null},{"ecosystem":"Go","name":"golang.org/x/net","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"0.60.0"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[],"references":["https://go.dev/cl/847185","https://go.dev/cl/847314","https://go.dev/issue/81857","https://groups.google.com/g/golang-announce/c/U2fTuyDJznI","https://groups.google.com/g/golang-announce/c/ZPwCyRUuGBs"],"sourceUrl":"https://osv.dev/vulnerability/GO-2026-6603","license":"OSV · upstream source license applies","key":"osv:GO-2026-6603","identifiers":["GO-2026-6603","BIT-golang-2026-78659","CVE-2026-78659"]},"retained":false,"historicalAffected":[]}],"coverage":[]}