diff --git a/news/13548.bugfix.rst b/news/13548.bugfix.rst
new file mode 100644
index 00000000000..1dff4989a5a
--- /dev/null
+++ b/news/13548.bugfix.rst
@@ -0,0 +1,2 @@
+Fix regression in configuration parsing that was turning a single value
+into a list and thus leading to a validation error.
diff --git a/src/pip/_internal/cli/parser.py b/src/pip/_internal/cli/parser.py
index f8b8ac43bec..3905a91f2e1 100644
--- a/src/pip/_internal/cli/parser.py
+++ b/src/pip/_internal/cli/parser.py
@@ -203,9 +203,9 @@ def _get_ordered_configuration_items(
                 if section in override_order:
                     section_items[section].append((key, val))
 
-            # Yield each group in their override order
-            for section in override_order:
-                yield from section_items[section]
+        # Yield each group in their override order
+        for section in override_order:
+            yield from section_items[section]
 
     def _update_defaults(self, defaults: dict[str, Any]) -> dict[str, Any]:
         """Updates the given defaults with values from the config files and
diff --git a/tests/functional/test_configuration.py b/tests/functional/test_configuration.py
index af3000e7f77..eb84343a6de 100644
--- a/tests/functional/test_configuration.py
+++ b/tests/functional/test_configuration.py
@@ -9,12 +9,14 @@
 import sys
 import textwrap
 
+import pytest
+
 from pip._internal.cli.status_codes import ERROR
 from pip._internal.configuration import CONFIG_BASENAME, Kind
 from pip._internal.configuration import get_configuration_files as _get_config_files
 from pip._internal.utils.compat import WINDOWS
 
-from tests.lib import PipTestEnvironment
+from tests.lib import PipTestEnvironment, TestData
 from tests.lib.configuration_helpers import ConfigurationMixin, kinds
 from tests.lib.venv import VirtualEnvironment
 
@@ -212,3 +214,21 @@ def test_config_separated(
             ),
             result.stdout,
         )
+
+    @pytest.mark.network
+    def test_editable_mode_default_config(
+        self, script: PipTestEnvironment, data: TestData
+    ) -> None:
+        """Test that setting default editable mode through configuration works
+        as expected.
+        """
+        script.pip(
+            "config", "--site", "set", "install.config-settings", "editable_mode=strict"
+        )
+        to_install = data.src.joinpath("simplewheel-1.0")
+        script.pip("install", "-e", to_install)
+        assert os.path.isdir(
+            os.path.join(
+                to_install, "build", "__editable__.simplewheel-1.0-py3-none-any"
+            )
+        )