diff --git a/lib/scm/scm.class.php b/lib/scm/scm.class.php
index 2ce9b6a05d..99cc11e015 100644
--- a/lib/scm/scm.class.php
+++ b/lib/scm/scm.class.php
@@ -226,7 +226,7 @@ class scm
      */
     public static function checkRevision($revision)
     {
-        if(preg_match('/[^a-z0-9\-\^]/i', $revision)) return false;
+        if(preg_match('/[^a-z0-9\-_\.\^]/i', $revision)) return false;
         return true;
     }
 }