diff --git a/backend/routers/files_read.py b/backend/routers/files_read.py
index 3f17b8f..8159aa9 100644
--- a/backend/routers/files_read.py
+++ b/backend/routers/files_read.py
@@ -246,6 +246,8 @@ def api_file_xlsx_dashboard(
     """
     if not check_vault_access(vault_name, current_user):
         raise HTTPException(status_code=403, detail=f"Accès refusé à la vault '{vault_name}'")
+    if chemin_exclu(vault_name, path):
+        raise HTTPException(status_code=404, detail=f"File not found: {path}")
     _vault_root = get_vault_root(vault_name)
     file_path = resolve_safe_path(_vault_root, path)
     if not file_path.is_file():
@@ -314,6 +316,9 @@ def api_file_xlsx_sheet(
     if not vault_data:
         raise HTTPException(status_code=404, detail=f"Vault '{vault_name}' not found")
 
+    if chemin_exclu(vault_name, path):
+        raise HTTPException(status_code=404, detail=f"File not found: {path}")
+
     file_path = resolve_safe_path(Path(vault_data["path"]), path)
     if not file_path.is_file():
         raise HTTPException(status_code=404, detail=f"File not found: {path}")