diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index 096a561c4..9d502acf5 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -1272,7 +1272,9 @@ ngx_http_core_try_files_phase(ngx_http_request_t *r,
 
             *e.pos = '\0';
 
-            if (alias && ngx_strncmp(name, clcf->name.data, alias) == 0) {
+            if (alias && alias != NGX_MAX_SIZE_T_VALUE
+                && ngx_strncmp(name, clcf->name.data, alias) == 0)
+            {
                 ngx_memmove(name, name + alias, len - alias);
                 path.len -= alias;
             }