diff --git a/src/auth/routes.py b/src/auth/routes.py
index 6bc5d5c..57b2281 100644
--- a/src/auth/routes.py
+++ b/src/auth/routes.py
@@ -100,7 +100,9 @@ def login():
         check_password_hash(_DUMMY_HASH, password)  # uniformiser le temps
         return _redirect_with_error("/connexion", "invalid_credentials", email)
 
-    if not check_password_hash(row["password_hash"], password):
+    if row["password_hash"] is None or not check_password_hash(
+        row["password_hash"], password
+    ):
         return _redirect_with_error("/connexion", "invalid_credentials", email)
 
     if not row["email_verified"]:
@@ -177,6 +179,8 @@ def change_password():
     password_confirm = request.form.get("password_confirm") or ""
 
     row = db.get_user_by_id(current_user.id)
+    if row["password_hash"] is None:
+        return _redirect_with_error("/compte/admin", "no_password_set")
     if not check_password_hash(row["password_hash"], current_pw):
         return _redirect_with_error("/compte/admin", "invalid_current_password")
 
@@ -231,7 +235,9 @@ def confirm_email_change():
 def delete_account():
     current_pw = request.form.get("current_password") or ""
     row = db.get_user_by_id(current_user.id)
-    if not check_password_hash(row["password_hash"], current_pw):
+    if row["password_hash"] is not None and not check_password_hash(
+        row["password_hash"], current_pw
+    ):
         return _redirect_with_error("/compte/admin", "invalid_current_password")
 
     user_id = current_user.id
diff --git a/src/auth/setup.py b/src/auth/setup.py
index 8703877..ea6c717 100644
--- a/src/auth/setup.py
+++ b/src/auth/setup.py
@@ -63,3 +63,8 @@ def init_auth(app: Flask) -> None:
             "LINKEDIN_CLIENT_ID non défini : la connexion LinkedIn échouera. "
             "Définissez LINKEDIN_CLIENT_ID / LINKEDIN_CLIENT_SECRET dans .env."
         )
+
+    if not os.getenv("APP_BASE_URL"):
+        logger.warning(
+            "APP_BASE_URL non défini : le callback LinkedIn produira une URI relative invalide."
+        )
diff --git a/src/pages/compte_admin.py b/src/pages/compte_admin.py
index 205b47c..09143a9 100644
--- a/src/pages/compte_admin.py
+++ b/src/pages/compte_admin.py
@@ -14,6 +14,7 @@ register_page(
 
 ERROR_MESSAGES = {
     "invalid_current_password": "Le mot de passe actuel est incorrect.",
+    "no_password_set": "Votre compte n'a pas de mot de passe (connexion via LinkedIn). Utilisez la réinitialisation de mot de passe pour en définir un.",
     "password_too_short": "Le nouveau mot de passe doit faire au moins 8 caractères.",
     "password_mismatch": "Les nouveaux mots de passe ne correspondent pas.",
     "invalid_email": "L'adresse email n'est pas valide.",