diff --git a/frictionless/fields/__spec__/test_string.py b/frictionless/fields/__spec__/test_string.py
index 24a83794f4..21817ffb58 100644
--- a/frictionless/fields/__spec__/test_string.py
+++ b/frictionless/fields/__spec__/test_string.py
@@ -24,6 +24,9 @@
         ("binary", "dGVzdA==", "dGVzdA=="),
         ("binary", "", None),
         ("binary", "string", None),
+        ("binary", "!!!!", None),
+        ("binary", "@@@@", None),
+        ("binary", "()()", None),
         ("binary", 0, None),
     ],
 )
diff --git a/frictionless/fields/string.py b/frictionless/fields/string.py
index 3fb4eeec5e..31b0453f0c 100644
--- a/frictionless/fields/string.py
+++ b/frictionless/fields/string.py
@@ -66,7 +66,7 @@ def value_reader(cell: Any):
                 if not isinstance(cell, str):
                     return None
                 try:
-                    base64.b64decode(cell)
+                    base64.b64decode(cell, validate=True)
                 except Exception:
                     return None
                 return cell