diff --git a/var/spack/repos/builtin/packages/flex/package.py b/var/spack/repos/builtin/packages/flex/package.py
index 23b3c8b21a..e4117877c1 100644
--- a/var/spack/repos/builtin/packages/flex/package.py
+++ b/var/spack/repos/builtin/packages/flex/package.py
@@ -31,6 +31,7 @@ class Flex(AutotoolsPackage):
     homepage = "https://github.com/westes/flex"
     url = "https://github.com/westes/flex/releases/download/v2.6.1/flex-2.6.1.tar.gz"
 
+    version('2.6.3', 'a5f65570cd9107ec8a8ec88f17b31bb1')
     # Problematic version:
     # See issue #2554; https://github.com/westes/flex/issues/113
     # version('2.6.2', 'cc6d76c333db7653d5caf423a3335239')