diff --git a/src/net/http/server.go b/src/net/http/server.go
index 6d325fdbc5..2855df0ff6 100644
--- a/src/net/http/server.go
+++ b/src/net/http/server.go
@@ -3420,7 +3420,7 @@ func (tw *timeoutWriter) writeHeaderLocked(code int) {
 	checkWriteHeaderCode(code)
 
 	switch {
-	case tw.timedOut:
+	case tw.timedOut, tw.clientHangup:
 		return
 	case tw.wroteHeader:
 		if tw.req != nil {