diff --git a/lib/hx509/version-script.map b/lib/hx509/version-script.map
index 1803eb8fb..68ef73e8e 100644
--- a/lib/hx509/version-script.map
+++ b/lib/hx509/version-script.map
@@ -100,6 +100,7 @@ HEIMDAL_X509_1.0 {
 		hx509_env_init;
 		hx509_env_lfind;
 		hx509_err;
+		hx509_free_error_string;
 		hx509_free_octet_string_list;
 		hx509_general_name_unparse;
 		hx509_get_error_string;