diff --git a/src/http/modules/ngx_http_dav_module.c b/src/http/modules/ngx_http_dav_module.c
index dd960ca27..1e66c2336 100644
--- a/src/http/modules/ngx_http_dav_module.c
+++ b/src/http/modules/ngx_http_dav_module.c
@@ -539,7 +539,7 @@ static ngx_int_t
 ngx_http_dav_copy_move_handler(ngx_http_request_t *r)
 {
     u_char                    *p, *host, *last, ch;
-    size_t                     len, root;
+    size_t                     len, root, alias;
     ngx_err_t                  err;
     ngx_int_t                  rc, depth;
     ngx_uint_t                 overwrite, slash, dir, flags;
@@ -649,15 +649,19 @@ destination_done:
     }
 
     clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
+    alias = clcf->alias;
 
-    if (clcf->alias
-        && clcf->alias != NGX_MAX_SIZE_T_VALUE
-        && duri.len < clcf->alias)
-    {
-        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
-                      "client sent invalid \"Destination\" header: \"%V\"",
-                      &dest->value);
-        return NGX_HTTP_BAD_REQUEST;
+    if (alias && alias != NGX_MAX_SIZE_T_VALUE && r->valid_location) {
+
+        if (alias > duri.len
+            || ngx_filename_cmp(duri.data, r->uri.data, alias) != 0)
+        {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "\"Destination\" URI \"%V\" must be "
+                          "within location prefix when using \"alias\"",
+                          &dest->value);
+            return NGX_HTTP_BAD_REQUEST;
+        }
     }
 
     depth = ngx_http_dav_depth(r, NGX_HTTP_DAV_INFINITY_DEPTH);
diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index 504e49eb2..7aa96206f 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -1994,6 +1994,12 @@ ngx_http_map_uri_to_path(ngx_http_request_t *r, ngx_str_t *path,
         return NULL;
     }
 
+    if (alias > r->uri.len && alias != NGX_MAX_SIZE_T_VALUE) {
+        ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
+                      "URI shorter than aliased URI part");
+        return NULL;
+    }
+
     if (clcf->root_lengths == NULL) {
 
         *root_length = clcf->root.len;