diff --git a/transport/internet/splithttp/upload_queue.go b/transport/internet/splithttp/upload_queue.go
index 2d1fb5f4..23124c4f 100644
--- a/transport/internet/splithttp/upload_queue.go
+++ b/transport/internet/splithttp/upload_queue.go
@@ -6,6 +6,7 @@ package splithttp
 import (
 	"container/heap"
 	"io"
+	"sync"
 
 	"github.com/xtls/xray-core/common/errors"
 )
@@ -16,11 +17,12 @@ type Packet struct {
 }
 
 type uploadQueue struct {
-	pushedPackets chan Packet
-	heap          uploadHeap
-	nextSeq       uint64
-	closed        bool
-	maxPackets    int
+	pushedPackets   chan Packet
+	writeCloseMutex sync.Mutex
+	heap            uploadHeap
+	nextSeq         uint64
+	closed          bool
+	maxPackets      int
 }
 
 func NewUploadQueue(maxPackets int) *uploadQueue {
@@ -34,6 +36,9 @@ func NewUploadQueue(maxPackets int) *uploadQueue {
 }
 
 func (h *uploadQueue) Push(p Packet) error {
+	h.writeCloseMutex.Lock()
+	defer h.writeCloseMutex.Unlock()
+
 	if h.closed {
 		return errors.New("splithttp packet queue closed")
 	}
@@ -43,6 +48,9 @@ func (h *uploadQueue) Push(p Packet) error {
 }
 
 func (h *uploadQueue) Close() error {
+	h.writeCloseMutex.Lock()
+	defer h.writeCloseMutex.Unlock()
+
 	h.closed = true
 	close(h.pushedPackets)
 	return nil