diff --git a/pkgs/development/interpreters/ruby/default.nix b/pkgs/development/interpreters/ruby/default.nix
index 9091d247d65a..02e76d5e127a 100644
--- a/pkgs/development/interpreters/ruby/default.nix
+++ b/pkgs/development/interpreters/ruby/default.nix
@@ -230,10 +230,10 @@ in {
   };
 
   ruby_2_6 = generic {
-    version = rubyVersion "2" "6" "3" "";
+    version = rubyVersion "2" "6" "4" "";
     sha256 = {
-      src = "1yw23hmllxsc4b7zqndn5l4d9503gdik6rsf3lfdkf12bxwx6zsp";
-      git = "1h4k2kw0vr4jh2ra9l89i8lnddfh2qfw67y9cknjylf7kw2m1pmh";
+      src = "0dvrw4g2igvjclxk9bmb9pf6mzxwm22zqvqa0abkfnshfnxdihag";
+      git = "1h4z66amjykpzl6lxx6yad2yfpwnwix4sw19bd96jnwg248kviqf";
     };
   };
 }
diff --git a/pkgs/development/interpreters/ruby/patchsets.nix b/pkgs/development/interpreters/ruby/patchsets.nix
index 429e5e210ed3..5bf59a96f741 100644
--- a/pkgs/development/interpreters/ruby/patchsets.nix
+++ b/pkgs/development/interpreters/ruby/patchsets.nix
@@ -16,7 +16,7 @@ rec {
     "${patchSet}/patches/ruby/2.5/head/railsexpress/02-improve-gc-stats.patch"
     "${patchSet}/patches/ruby/2.5/head/railsexpress/03-more-detailed-stacktrace.patch"
   ];
-  "2.6.3" = ops useRailsExpress [
+  "2.6.4" = ops useRailsExpress [
     "${patchSet}/patches/ruby/2.6/head/railsexpress/01-fix-broken-tests-caused-by-ad.patch"
     "${patchSet}/patches/ruby/2.6/head/railsexpress/02-improve-gc-stats.patch"
     "${patchSet}/patches/ruby/2.6/head/railsexpress/03-more-detailed-stacktrace.patch"