{"schema_version":"1.9.0","id":"GO-2026-6607","published":"2026-10-08T22:31:09Z","modified":"2026-10-16T09:55:33.249742867Z","aliases":["BIT-golang-2026-97031","CVE-2026-97031"],"summary":"Reject malformed ECH outer extension references in crypto/tls","details":"Multiple ECH outer extension references are not permitted under RFC 9849; previously, a client could send a well-crafted packet that could trigger memory exhaustion in the server process by specifying multiple references.\n\nWe now reject these as malformed and curb the memory amplification vector as a result.","affected":[{"package":{"name":"stdlib","ecosystem":"Go","purl":"pkg:golang/stdlib"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.26.9"},{"introduced":"1.27.0-0"},{"fixed":"1.27.2"}]}],"ecosystem_specific":{"imports":[{"path":"crypto/tls","symbols":["Conn.Handshake","Conn.HandshakeContext","Conn.Read","Conn.Write","Dial","DialWithDialer","Dialer.Dial","Dialer.DialContext","QUICConn.Start","decodeInnerClientHello"]}]},"database_specific":{"source":"https://vuln.go.dev/ID/GO-2026-6607.json"}}],"references":[{"type":"FIX","url":"https://go.dev/cl/847312"},{"type":"REPORT","url":"https://go.dev/issue/81855"},{"type":"WEB","url":"https://groups.google.com/g/golang-announce/c/U2fTuyDJznI"}],"database_specific":{"review_status":"REVIEWED","url":"https://pkg.go.dev/vuln/GO-2026-6607"}}