diff --git a/Lib/fontTools/subset.py b/Lib/fontTools/subset.py
index d8d46af..45bd457 100644
--- a/Lib/fontTools/subset.py
+++ b/Lib/fontTools/subset.py
@@ -1701,6 +1701,7 @@
 def closure_glyphs(self, s):
   tables = [t for t in self.tables if t.isUnicode()]
   for u in s.unicodes_requested:
+    found = False
     for table in tables:
       if table.format == 14:
         for l in table.uvsDict.values():