diff --git a/libcontainer/factory_linux.go b/libcontainer/factory_linux.go
index 3a0ad81e..26035c3e 100644
--- a/libcontainer/factory_linux.go
+++ b/libcontainer/factory_linux.go
@@ -26,7 +26,7 @@ const (
 )
 
 var (
-	idRegex  = regexp.MustCompile(`^[\w-\.]+$`)
+	idRegex  = regexp.MustCompile(`^[\w+-\.]+$`)
 	maxIdLen = 1024
 )