diff --git a/common/menu.c b/common/menu.c
index 5a8a2760..f094ea54 100644
--- a/common/menu.c
+++ b/common/menu.c
@@ -827,7 +827,7 @@ noreturn void _menu(bool first_run) {
     if (interface_help_colour_str != NULL) {
         interface_help_colour[3] = interface_help_colour_str[0];
         interface_help_colour_bright[3] = interface_help_colour_str[0];
-        pmm_free(interface_help_colour_str, strlen(interface_help_colour_str));
+        pmm_free(interface_help_colour_str, strlen(interface_help_colour_str) + 1);
     }
 
     menu_branding = config_get_value(NULL, 0, "INTERFACE_BRANDING");