fluent/fluentd · error · RuntimeError

BUG: failed to verify certification and to handle it correct

Error message

BUG: failed to verify certification and to handle it correctly while connecting host #{host} as #{fqdn}

What it means

Error "BUG: failed to verify certification and to handle it correctly while connecting host #{host} as #{fqdn}" thrown in fluent/fluentd.

Source

Thrown at lib/fluent/plugin_helper/socket.rb:188

            Timeout.timeout(connect_timeout) { sock.connect }
          rescue Timeout::Error
            log.warn "timeout while connecting tls session", host: host
            sock.close rescue nil
            raise
          end
        else
          sock.connect
        end

        begin
          if verify_fqdn
            log.trace "checking peer's certificate", subject: sock.peer_cert.subject
            sock.post_connection_check(fqdn)
            verify = sock.verify_result
            if verify != OpenSSL::X509::V_OK
              err_name = Socket.tls_verify_result_name(verify)
              log.warn "BUG: failed to verify certification while connecting (but not raised, why?)", host: host, fqdn: fqdn, error: err_name
              raise RuntimeError, "BUG: failed to verify certification and to handle it correctly while connecting host #{host} as #{fqdn}"
            end
          end
        rescue OpenSSL::SSL::SSLError => e
          log.warn "failed to verify certification while connecting tls session", host: host, fqdn: fqdn, error: e
          raise
        end

        if block
          begin
            block.call(sock)
          ensure
            sock.close rescue nil
          end
        else
          sock
        end
      end

View on GitHub (pinned to dd45c6e18d)

When it happens

Trigger: Thrown at lib/fluent/plugin_helper/socket.rb:188 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• SSL/TLS and certificate errors — how TLS handshakes and certificate validation fail.

AI-assisted analysis of fluent/fluentd@dd45c6e18d (2026-08-21). Data as JSON: /api/errors/d52409e9e7935153. Report an issue: GitHub.