diff --git a/src/go.mod b/src/go.mod
index 0d7d70f0..90af2a7 100644
--- a/src/go.mod
+++ b/src/go.mod
@@ -4,7 +4,7 @@
 
 require (
 	golang.org/x/crypto v0.0.0-20190611184440-5c40567a22f8
-	golang.org/x/net v0.0.0-20190607181551-461777fb6f67
+	golang.org/x/net v0.0.0-20190813141303-74dc4d7220e7
 	golang.org/x/sys v0.0.0-20190529130038-5219a1e1c5f8 // indirect
 	golang.org/x/text v0.3.2 // indirect
 )
diff --git a/src/go.sum b/src/go.sum
index 363ee7a..e358118 100644
--- a/src/go.sum
+++ b/src/go.sum
@@ -2,8 +2,8 @@
 golang.org/x/crypto v0.0.0-20190611184440-5c40567a22f8 h1:1wopBVtVdWnn03fZelqdXTqk7U7zPQCb+T4rbU9ZEoU=
 golang.org/x/crypto v0.0.0-20190611184440-5c40567a22f8/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20190607181551-461777fb6f67 h1:rJJxsykSlULwd2P2+pg/rtnwN2FrWp4IuCxOSyS0V00=
-golang.org/x/net v0.0.0-20190607181551-461777fb6f67/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20190813141303-74dc4d7220e7 h1:fHDIZ2oxGnUZRN6WgWFCbYBjH9uqVPRCUVUDhs0wnbA=
+golang.org/x/net v0.0.0-20190813141303-74dc4d7220e7/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190529130038-5219a1e1c5f8 h1:2WjIC11WRITGlVWmyLXKjzIVj1ZwoWZ//tadeUUV6/o=
diff --git a/src/net/http/h2_bundle.go b/src/net/http/h2_bundle.go
index 173622f..53cc5bd 100644
--- a/src/net/http/h2_bundle.go
+++ b/src/net/http/h2_bundle.go
@@ -3611,10 +3611,11 @@
 }
 
 const (
-	http2prefaceTimeout        = 10 * time.Second
-	http2firstSettingsTimeout  = 2 * time.Second // should be in-flight with preface anyway
-	http2handlerChunkWriteSize = 4 << 10
-	http2defaultMaxStreams     = 250 // TODO: make this 100 as the GFE seems to?
+	http2prefaceTimeout         = 10 * time.Second
+	http2firstSettingsTimeout   = 2 * time.Second // should be in-flight with preface anyway
+	http2handlerChunkWriteSize  = 4 << 10
+	http2defaultMaxStreams      = 250 // TODO: make this 100 as the GFE seems to?
+	http2maxQueuedControlFrames = 10000
 )
 
 var (
@@ -3722,6 +3723,15 @@
 	return http2defaultMaxStreams
 }
 
+// maxQueuedControlFrames is the maximum number of control frames like
+// SETTINGS, PING and RST_STREAM that will be queued for writing before
+// the connection is closed to prevent memory exhaustion attacks.
+func (s *http2Server) maxQueuedControlFrames() int {
+	// TODO: if anybody asks, add a Server field, and remember to define the
+	// behavior of negative values.
+	return http2maxQueuedControlFrames
+}
+
 type http2serverInternalState struct {
 	mu          sync.Mutex
 	activeConns map[*http2serverConn]struct{}
@@ -4065,6 +4075,7 @@
 	sawFirstSettings            bool // got the initial SETTINGS frame after the preface
 	needToSendSettingsAck       bool
 	unackedSettings             int    // how many SETTINGS have we sent without ACKs?
+	queuedControlFrames         int    // control frames in the writeSched queue
 	clientMaxStreams            uint32 // SETTINGS_MAX_CONCURRENT_STREAMS from client (our PUSH_PROMISE limit)
 	advMaxStreams               uint32 // our SETTINGS_MAX_CONCURRENT_STREAMS advertised the client
 	curClientStreams            uint32 // number of open streams initiated by the client
@@ -4456,6 +4467,14 @@
 			}
 		}
 
+		// If the peer is causing us to generate a lot of control frames,
+		// but not reading them from us, assume they are trying to make us
+		// run out of memory.
+		if sc.queuedControlFrames > sc.srv.maxQueuedControlFrames() {
+			sc.vlogf("http2: too many control frames in send queue, closing connection")
+			return
+		}
+
 		// Start the shutdown timer after sending a GOAWAY. When sending GOAWAY
 		// with no error code (graceful shutdown), don't start the timer until
 		// all open streams have been completed.
@@ -4657,6 +4676,14 @@
 	}
 
 	if !ignoreWrite {
+		if wr.isControl() {
+			sc.queuedControlFrames++
+			// For extra safety, detect wraparounds, which should not happen,
+			// and pull the plug.
+			if sc.queuedControlFrames < 0 {
+				sc.conn.Close()
+			}
+		}
 		sc.writeSched.Push(wr)
 	}
 	sc.scheduleFrameWrite()
@@ -4774,10 +4801,8 @@
 // If a frame is already being written, nothing happens. This will be called again
 // when the frame is done being written.
 //
-// If a frame isn't being written we need to send one, the best frame
-// to send is selected, preferring first things that aren't
-// stream-specific (e.g. ACKing settings), and then finding the
-// highest priority stream.
+// If a frame isn't being written and we need to send one, the best frame
+// to send is selected by writeSched.
 //
 // If a frame isn't being written and there's nothing else to send, we
 // flush the write buffer.
@@ -4805,6 +4830,9 @@
 		}
 		if !sc.inGoAway || sc.goAwayCode == http2ErrCodeNo {
 			if wr, ok := sc.writeSched.Pop(); ok {
+				if wr.isControl() {
+					sc.queuedControlFrames--
+				}
 				sc.startFrameWrite(wr)
 				continue
 			}
@@ -5097,6 +5125,8 @@
 	if err := f.ForeachSetting(sc.processSetting); err != nil {
 		return err
 	}
+	// TODO: judging by RFC 7540, Section 6.5.3 each SETTINGS frame should be
+	// acknowledged individually, even if multiple are received before the ACK.
 	sc.needToSendSettingsAck = true
 	sc.scheduleFrameWrite()
 	return nil
@@ -7451,7 +7481,7 @@
 		req.Method != "HEAD" {
 		// Request gzip only, not deflate. Deflate is ambiguous and
 		// not as universally supported anyway.
-		// See: http://www.gzip.org/zlib/zlib_faq.html#faq38
+		// See: https://zlib.net/zlib_faq.html#faq39
 		//
 		// Note that we don't request this for HEAD requests,
 		// due to a bug in nginx:
@@ -9445,7 +9475,7 @@
 
 	// Pop dequeues the next frame to write. Returns false if no frames can
 	// be written. Frames with a given wr.StreamID() are Pop'd in the same
-	// order they are Push'd.
+	// order they are Push'd. No frames should be discarded except by CloseStream.
 	Pop() (wr http2FrameWriteRequest, ok bool)
 }
 
@@ -9489,6 +9519,12 @@
 	return wr.stream.id
 }
 
+// isControl reports whether wr is a control frame for MaxQueuedControlFrames
+// purposes. That includes non-stream frames and RST_STREAM frames.
+func (wr http2FrameWriteRequest) isControl() bool {
+	return wr.stream == nil
+}
+
 // DataSize returns the number of flow control bytes that must be consumed
 // to write this entire frame. This is 0 for non-DATA frames.
 func (wr http2FrameWriteRequest) DataSize() int {
diff --git a/src/vendor/golang.org/x/net/lif/zsys_solaris_amd64.go b/src/vendor/golang.org/x/net/lif/zsys_solaris_amd64.go
index b5e999b..d7a70d4 100644
--- a/src/vendor/golang.org/x/net/lif/zsys_solaris_amd64.go
+++ b/src/vendor/golang.org/x/net/lif/zsys_solaris_amd64.go
@@ -1,4 +1,4 @@
-// Created by cgo -godefs - DO NOT EDIT
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
 // cgo -godefs defs_solaris.go
 
 package lif
diff --git a/src/vendor/golang.org/x/net/route/zsys_darwin.go b/src/vendor/golang.org/x/net/route/zsys_darwin.go
index 4e2e1ab..19e4133 100644
--- a/src/vendor/golang.org/x/net/route/zsys_darwin.go
+++ b/src/vendor/golang.org/x/net/route/zsys_darwin.go
@@ -1,4 +1,4 @@
-// Created by cgo -godefs - DO NOT EDIT
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
 // cgo -godefs defs_darwin.go
 
 package route
diff --git a/src/vendor/golang.org/x/net/route/zsys_dragonfly.go b/src/vendor/golang.org/x/net/route/zsys_dragonfly.go
index 719c88d..8ed2d4d5 100644
--- a/src/vendor/golang.org/x/net/route/zsys_dragonfly.go
+++ b/src/vendor/golang.org/x/net/route/zsys_dragonfly.go
@@ -1,4 +1,4 @@
-// Created by cgo -godefs - DO NOT EDIT
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
 // cgo -godefs defs_dragonfly.go
 
 package route
diff --git a/src/vendor/golang.org/x/net/route/zsys_freebsd_386.go b/src/vendor/golang.org/x/net/route/zsys_freebsd_386.go
index b03bc01..f36aaad 100644
--- a/src/vendor/golang.org/x/net/route/zsys_freebsd_386.go
+++ b/src/vendor/golang.org/x/net/route/zsys_freebsd_386.go
@@ -1,4 +1,4 @@
-// Created by cgo -godefs - DO NOT EDIT
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
 // cgo -godefs defs_freebsd.go
 
 package route
diff --git a/src/vendor/golang.org/x/net/route/zsys_freebsd_amd64.go b/src/vendor/golang.org/x/net/route/zsys_freebsd_amd64.go
index 0b675b3..4c639b8 100644
--- a/src/vendor/golang.org/x/net/route/zsys_freebsd_amd64.go
+++ b/src/vendor/golang.org/x/net/route/zsys_freebsd_amd64.go
@@ -1,4 +1,4 @@
-// Created by cgo -godefs - DO NOT EDIT
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
 // cgo -godefs defs_freebsd.go
 
 package route
diff --git a/src/vendor/golang.org/x/net/route/zsys_freebsd_arm.go b/src/vendor/golang.org/x/net/route/zsys_freebsd_arm.go
index 58f8ea1..710c147 100644
--- a/src/vendor/golang.org/x/net/route/zsys_freebsd_arm.go
+++ b/src/vendor/golang.org/x/net/route/zsys_freebsd_arm.go
@@ -1,4 +1,4 @@
-// Created by cgo -godefs - DO NOT EDIT
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
 // cgo -godefs defs_freebsd.go
 
 package route
diff --git a/src/vendor/golang.org/x/net/route/zsys_netbsd.go b/src/vendor/golang.org/x/net/route/zsys_netbsd.go
index e0df45e..b4f66ca 100644
--- a/src/vendor/golang.org/x/net/route/zsys_netbsd.go
+++ b/src/vendor/golang.org/x/net/route/zsys_netbsd.go
@@ -1,4 +1,4 @@
-// Created by cgo -godefs - DO NOT EDIT
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
 // cgo -godefs defs_netbsd.go
 
 package route
diff --git a/src/vendor/golang.org/x/net/route/zsys_openbsd.go b/src/vendor/golang.org/x/net/route/zsys_openbsd.go
index db8c8ef..1021b4c 100644
--- a/src/vendor/golang.org/x/net/route/zsys_openbsd.go
+++ b/src/vendor/golang.org/x/net/route/zsys_openbsd.go
@@ -1,4 +1,4 @@
-// Created by cgo -godefs - DO NOT EDIT
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
 // cgo -godefs defs_openbsd.go
 
 package route
diff --git a/src/vendor/modules.txt b/src/vendor/modules.txt
index 20f261b..453a312 100644
--- a/src/vendor/modules.txt
+++ b/src/vendor/modules.txt
@@ -7,7 +7,7 @@
 golang.org/x/crypto/internal/chacha20
 golang.org/x/crypto/internal/subtle
 golang.org/x/crypto/poly1305
-# golang.org/x/net v0.0.0-20190607181551-461777fb6f67
+# golang.org/x/net v0.0.0-20190813141303-74dc4d7220e7
 golang.org/x/net/dns/dnsmessage
 golang.org/x/net/http/httpguts
 golang.org/x/net/http/httpproxy