diff --git a/src/mailparser/utils.py b/src/mailparser/utils.py
index 7e4f123..dbc6f96 100644
--- a/src/mailparser/utils.py
+++ b/src/mailparser/utils.py
@@ -19,6 +19,7 @@
 import base64
 import datetime
 import email
+import email.header
 import email.utils
 import functools
 import hashlib
@@ -107,6 +108,9 @@ def ported_string(raw_data, encoding="utf-8", errors="ignore"):
     if not raw_data:
         return str()
 
+    if isinstance(raw_data, email.header.Header):
+        return str(raw_data)
+
     if isinstance(raw_data, str):
         return raw_data
 
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 20f0df0..7665431 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -587,6 +587,19 @@ def test_receiveds_format_delay_no_previous_date(self):
         # But should have a valid date itself
         self.assertIsNotNone(result[1].get("date_utc"))
 
+    def test_ported_string_handles_header_object(self):
+        """
+        Test that ported_string can accept an email.header.Header object
+        and return a decoded string without crashing.
+        """
+        from email.header import Header
+
+        raw_val = 'attachment;\r\nfilename="Just a text – 2026.pdf'
+        header_obj = Header(raw_val, charset="utf-8")
+        result = ported_string(header_obj)
+        self.assertIsInstance(result, str)
+        self.assertEqual(result, raw_val)
+
     def test_parse_received_envelope_from_with_angle_brackets(self):
         """Test utils.py:294-296 — envelope-from clause with angle-bracket match"""
         # When envelope-from keyword is present AND its value has angle