diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index 55ec39d242..2a9c468560 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -570,7 +570,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
             if (t == value_t::array || t == value_t::object)
             {
                 // flatten the current json_value to a heap-allocated stack
-                std::vector<basic_json> stack;
+                std::vector<basic_json, allocator_type> stack;
 
                 // move the top-level items to stack
                 if (t == value_t::array)
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 8e7ac2017e..0bc1c4e713 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -20673,7 +20673,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
             if (t == value_t::array || t == value_t::object)
             {
                 // flatten the current json_value to a heap-allocated stack
-                std::vector<basic_json> stack;
+                std::vector<basic_json, allocator_type> stack;
 
                 // move the top-level items to stack
                 if (t == value_t::array)