1 files changed, 1 insertions, 1 deletions
diff --git a/bottle.py b/bottle.py
index c13c99e..45e85d1 100755
--- a/bottle.py
+++ b/bottle.py
@@ -2878,7 +2878,7 @@ def static_file(filename, root,
 
     root = os.path.join(os.path.abspath(root), '')
     filename = os.path.abspath(os.path.join(root, filename.strip('/\\')))
-    headers = headers or {}
+    headers = headers.copy() if headers else {}
 
     if not filename.startswith(root):
         return HTTPError(403, "Access denied.")