diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index df41aa621..281a3ab53 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -1,6 +1,8 @@
 fish ?.?.? (released ???)
 =========================
 
+This release fixes a regression in 4.7.0 that caused the web config (``fish_config``) to fail to start (:issue:`12717`).
+
 fish 4.7.0 (released May 05, 2026)
 ==================================
 
diff --git a/share/config.fish b/share/config.fish
index b4b39ddb6..b46cadaec 100644
--- a/share/config.fish
+++ b/share/config.fish
@@ -208,6 +208,8 @@ end
 
 if status is-interactive
     __fish_migrate
+end
+if status is-interactive || set -qgx __fish_force_load_default_theme
     fish_config theme choose default --no-override
 end
 
diff --git a/share/tools/web_config/webconfig.py b/share/tools/web_config/webconfig.py
index fcfbc2c15..4385588f7 100755
--- a/share/tools/web_config/webconfig.py
+++ b/share/tools/web_config/webconfig.py
@@ -100,13 +100,14 @@ def is_chromeos_garcon():
         return False
 
 
-def run_fish_cmd(text, strict=False):
+def run_fish_cmd(text, strict=False, env=None):
     print("$ " + text)
     p = subprocess.Popen(
         [FISH_BIN_PATH],
         stdin=subprocess.PIPE,
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
+        env=env,
     )
     out, err = p.communicate(text.encode("utf-8"))
     out = out.decode("utf-8", "replace")
@@ -811,7 +812,8 @@ class FishConfigHTTPRequestHandler(SimpleHTTPServer.SimpleHTTPRequestHandler):
                 TERMINAL_COLOR_THEME
             )
             + "or __fish_color_theme=unknown __fish_apply_theme\n"
-            + "__fish_theme_export_for_webconfig"
+            + "__fish_theme_export_for_webconfig",
+            env=os.environ | {"__fish_force_load_default_theme": "1"},
         )
         assert err == ""