diff --git a/modules/mappers/mod_dir.c b/modules/mappers/mod_dir.c
index 4364ff9..a09c6098 100644
--- a/modules/mappers/mod_dir.c
+++ b/modules/mappers/mod_dir.c
@@ -260,6 +260,11 @@ static int fixup_dir(request_rec *r)
         return HTTP_MOVED_PERMANENTLY;
     }
 
+    if (r->filename == 0 || r->filename[0] == '\0'
+            || r->filename[strlen(r->filename) - 1] != '/') {
+        return DECLINED;
+    }
+
     if (d->index_names) {
         names_ptr = (char **)d->index_names->elts;
         num_names = d->index_names->nelts;