diff --git a/include/nlohmann/detail/output/serializer.hpp b/include/nlohmann/detail/output/serializer.hpp
index 0b608f8e2d..3d546c2706 100644
--- a/include/nlohmann/detail/output/serializer.hpp
+++ b/include/nlohmann/detail/output/serializer.hpp
@@ -128,7 +128,7 @@ class serializer
                     const auto new_indent = current_indent + indent_step;
                     if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent))
                     {
-                        indent_string.resize(indent_string.size() * 2, ' ');
+                        indent_string.resize((std::max)(indent_string.size() * 2, static_cast<typename string_t::size_type>(new_indent)), ' ');
                     }
 
                     // first n-1 elements
@@ -201,7 +201,7 @@ class serializer
                     const auto new_indent = current_indent + indent_step;
                     if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent))
                     {
-                        indent_string.resize(indent_string.size() * 2, ' ');
+                        indent_string.resize((std::max)(indent_string.size() * 2, static_cast<typename string_t::size_type>(new_indent)), ' ');
                     }
 
                     // first n-1 elements
@@ -262,7 +262,7 @@ class serializer
                     const auto new_indent = current_indent + indent_step;
                     if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent))
                     {
-                        indent_string.resize(indent_string.size() * 2, ' ');
+                        indent_string.resize((std::max)(indent_string.size() * 2, static_cast<typename string_t::size_type>(new_indent)), ' ');
                     }
 
                     o->write_characters(indent_string.c_str(), new_indent);
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 03d2351736..5d66ee375d 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -19835,7 +19835,7 @@ class serializer
                     const auto new_indent = current_indent + indent_step;
                     if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent))
                     {
-                        indent_string.resize(indent_string.size() * 2, ' ');
+                        indent_string.resize((std::max)(indent_string.size() * 2, static_cast<typename string_t::size_type>(new_indent)), ' ');
                     }
 
                     // first n-1 elements
@@ -19908,7 +19908,7 @@ class serializer
                     const auto new_indent = current_indent + indent_step;
                     if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent))
                     {
-                        indent_string.resize(indent_string.size() * 2, ' ');
+                        indent_string.resize((std::max)(indent_string.size() * 2, static_cast<typename string_t::size_type>(new_indent)), ' ');
                     }
 
                     // first n-1 elements
@@ -19969,7 +19969,7 @@ class serializer
                     const auto new_indent = current_indent + indent_step;
                     if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent))
                     {
-                        indent_string.resize(indent_string.size() * 2, ' ');
+                        indent_string.resize((std::max)(indent_string.size() * 2, static_cast<typename string_t::size_type>(new_indent)), ' ');
                     }
 
                     o->write_characters(indent_string.c_str(), new_indent);
diff --git a/tests/src/unit-serialization.cpp b/tests/src/unit-serialization.cpp
index f55ed84704..44ee0a5bc2 100644
--- a/tests/src/unit-serialization.cpp
+++ b/tests/src/unit-serialization.cpp
@@ -150,6 +150,36 @@ TEST_CASE("serialization")
         }
     }
 
+    SECTION("dump with large indentation")
+    {
+        // the indentation buffer starts at 512 characters and grows on demand;
+        // a width that needs more room than a single doubling provides must keep
+        // growing the buffer rather than emit past its end
+        const unsigned int width = 1100;
+
+        SECTION("object")
+        {
+            const json j = {{"outer", {{"inner", 1}}}};
+            const std::string s = j.dump(static_cast<int>(width));
+            CHECK(s.find('\n' + std::string(width, ' ') + "\"outer\"") != std::string::npos);
+            CHECK(s.find('\n' + std::string(2 * width, ' ') + "\"inner\"") != std::string::npos);
+        }
+
+        SECTION("array")
+        {
+            const json j = json::array({json::array({1})});
+            const std::string s = j.dump(static_cast<int>(width));
+            CHECK(s.find('\n' + std::string(2 * width, ' ') + '1') != std::string::npos);
+        }
+
+        SECTION("binary")
+        {
+            const json j = json::binary({1, 2, 3});
+            const std::string s = j.dump(static_cast<int>(width));
+            CHECK(s.find('\n' + std::string(width, ' ') + "\"bytes\"") != std::string::npos);
+        }
+    }
+
     SECTION("to_string")
     {
         auto test = [&](std::string const & input, std::string const & expected)