diff --git a/lib/spack/spack/cmd/extensions.py b/lib/spack/spack/cmd/extensions.py
index f6ccd7b5151..3b189895b0b 100644
--- a/lib/spack/spack/cmd/extensions.py
+++ b/lib/spack/spack/cmd/extensions.py
@@ -93,5 +93,5 @@ def extensions(parser, args):
     if not activated:
         tty.msg("None activated.")
         return
-    tty.msg("%d currently activated:" % len(exts))
-    spack.cmd.find.display_specs(installed, mode=args.mode)
+    tty.msg("%d currently activated:" % len(activated))
+    spack.cmd.find.display_specs(activated, mode=args.mode)