diff --git a/ruby.yaml b/ruby.yaml
index dc06763..cd4e5b7 100644
--- a/ruby.yaml
+++ b/ruby.yaml
@@ -31,7 +31,8 @@ data:
                 rationale: An interpreter of object-oriented scripting language
                 multilib: [x86_64]
                 buildorder: 101
-                ref: master
+                # Set a reference on master to guarantee the Ruby version 2.6.
+                ref: ea106d1
             rubygem-abrt:
                 # From rubygem-abrt.spec Summary
                 rationale: >-