diff --git a/ngx_rtmp.h b/ngx_rtmp.h
index e6c34d9..cbe6a93 100644
--- a/ngx_rtmp.h
+++ b/ngx_rtmp.h
@@ -135,6 +135,8 @@ typedef struct {
 #define NGX_RTMP_MSG_AGGREGATE          22
 #define NGX_RTMP_MSG_MAX                22
 
+#define NGX_RTMP_MAX_CHUNK_SIZE         10485760
+
 #define NGX_RTMP_CONNECT                NGX_RTMP_MSG_MAX + 1
 #define NGX_RTMP_DISCONNECT             NGX_RTMP_MSG_MAX + 2
 #define NGX_RTMP_HANDSHAKE_DONE         NGX_RTMP_MSG_MAX + 3
diff --git a/ngx_rtmp_handler.c b/ngx_rtmp_handler.c
index ac78a6f..17eadee 100644
--- a/ngx_rtmp_handler.c
+++ b/ngx_rtmp_handler.c
@@ -821,6 +821,12 @@ ngx_rtmp_set_chunk_size(ngx_rtmp_session_t *s, ngx_uint_t size)
     ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
         "setting chunk_size=%ui", size);
 
+    if (size > NGX_RTMP_MAX_CHUNK_SIZE) {
+        ngx_log_error(NGX_LOG_ALERT, s->connection->log, 0,
+                      "too big RTMP chunk size:%ui", size);
+        return NGX_ERROR;
+    }
+
     cscf = ngx_rtmp_get_module_srv_conf(s, ngx_rtmp_core_module);
 
     s->in_old_pool = s->in_pool;