diff --git a/project/Core/Src/tcp_cmd.c b/project/Core/Src/tcp_cmd.c
index 37395d5..9a602fa 100644
--- a/project/Core/Src/tcp_cmd.c
+++ b/project/Core/Src/tcp_cmd.c
@@ -76,6 +76,9 @@ void tcp_cmd_remove_newline(char* str, size_t len) {
 
 char* tcp_cmd_remove_leading_space(char* str, size_t len) {
     size_t i = 0;
+    if (str == NULL) {
+        return NULL;
+    }
     while (str[i] != '\0' && i < len) {
         if (isspace((int)str[i]) == 0) {
             return &str[i];