diff --git a/lib/gitlab/etag_caching/store.rb b/lib/gitlab/etag_caching/store.rb
index 0039fc01c8f..17750fe803e 100644
--- a/lib/gitlab/etag_caching/store.rb
+++ b/lib/gitlab/etag_caching/store.rb
@@ -25,6 +25,8 @@ module Gitlab
       end
 
       def redis_key(key)
+        raise 'Invalid key' unless Gitlab::EtagCaching::Router.match(key)
+        
         "#{REDIS_NAMESPACE}#{key}"
       end
     end