diff --git a/safe.c b/safe.c
index 7f3a412686..d790156c03 100644
--- a/safe.c
+++ b/safe.c
@@ -110,8 +110,8 @@ rb_insecure_operation(void)
 {
     ID caller_name = rb_frame_callee();
     if (caller_name) {
-	rb_raise(rb_eSecurityError, "Insecure operation - %s",
-		 rb_id2name(caller_name));
+	rb_raise(rb_eSecurityError, "Insecure operation - %"PRIsVALUE,
+		 rb_id2str(caller_name));
     }
     else {
 	rb_raise(rb_eSecurityError, "Insecure operation: -r");
diff --git a/test/ruby/test_file.rb b/test/ruby/test_file.rb
index 0825c5dd7b..16b76b71fe 100644
--- a/test/ruby/test_file.rb
+++ b/test/ruby/test_file.rb
@@ -390,6 +390,12 @@ class TestFile < Test::Unit::TestCase
     (0..1).each do |level|
       assert_nothing_raised(SecurityError, bug5374) {in_safe[level]}
     end
+    def (s = Object.new).to_path; "".taint; end
+    m = "\u{691c 67fb}"
+    (c = Class.new(File)).singleton_class.class_eval {alias_method m, :stat}
+    assert_raise_with_message(SecurityError, /#{m}/) {
+      proc {$SAFE = 3; c.__send__(m, s)}.call
+    }
   end
 
   if /(bcc|ms|cyg)win|mingw|emx/ =~ RUBY_PLATFORM