diff --git a/src/http/ngx_http_script.c b/src/http/ngx_http_script.c
index 8f7b548cc..ddae0c1cb 100644
--- a/src/http/ngx_http_script.c
+++ b/src/http/ngx_http_script.c
@@ -150,7 +150,9 @@ ngx_http_compile_complex_value(ngx_http_compile_complex_value_t *ccv)
 
     for (i = 0; i < v->len; i++) {
         if (v->data[i] == '$') {
-            if (v->data[i + 1] >= '1' && v->data[i + 1] <= '9') {
+            if (i + 1 < v->len
+                && v->data[i + 1] >= '1' && v->data[i + 1] <= '9')
+            {
                 nc++;
 
             } else {
diff --git a/src/stream/ngx_stream_script.c b/src/stream/ngx_stream_script.c
index c447e152f..175e44194 100644
--- a/src/stream/ngx_stream_script.c
+++ b/src/stream/ngx_stream_script.c
@@ -151,7 +151,9 @@ ngx_stream_compile_complex_value(ngx_stream_compile_complex_value_t *ccv)
 
     for (i = 0; i < v->len; i++) {
         if (v->data[i] == '$') {
-            if (v->data[i + 1] >= '1' && v->data[i + 1] <= '9') {
+            if (i + 1 < v->len
+                && v->data[i + 1] >= '1' && v->data[i + 1] <= '9')
+            {
                 nc++;
 
             } else {