diff --git a/hwilib/descriptor.py b/hwilib/descriptor.py
index 1373ad2d2..1c05ad225 100644
--- a/hwilib/descriptor.py
+++ b/hwilib/descriptor.py
@@ -543,9 +543,11 @@ def _get_func_expr(s: str) -> Tuple[str, str]:
     try:
         start = s.index("(")
         end = s.rindex(")")
-        return s[0:start], s[start + 1:end]
     except ValueError:
         raise ValueError("A matching pair of parentheses cannot be found")
+    if end != len(s) - 1:
+        raise ValueError("Trailing characters '{}' after descriptor".format(s[end + 1:]))
+    return s[0:start], s[start + 1:end]
 
 
 def _get_const(s: str, const: str) -> str:
diff --git a/test/test_descriptor.py b/test/test_descriptor.py
index dca4fbe80..1fd01c93f 100755
--- a/test/test_descriptor.py
+++ b/test/test_descriptor.py
@@ -165,6 +165,13 @@ def test_parse_descriptor_with_key_at_end_without_origin(self):
     def test_parse_empty_descriptor(self):
         self.assertRaises(ValueError, parse_descriptor, "")
 
+    def test_parse_descriptor_trailing_characters(self):
+        key = "02c97dc3f4420402e01a113984311bf4a1b8de376cac0bdcfaf1b3ac81f13433c7"
+        with self.assertRaisesRegex(ValueError, "Trailing characters"):
+            parse_descriptor("pkh({})abc".format(key))
+        with self.assertRaisesRegex(ValueError, "Trailing characters"):
+            parse_descriptor("sh(wpkh({}))x".format(key))
+
     def test_parse_descriptor_replace_h(self):
         d = "wpkh([00000001/84h/1h/0h]tpubD6NzVbkrYhZ4WaWSyoBvQwbpLkojyoTZPRsgXELWz3Popb3qkjcJyJUGLnL4qHHoQvao8ESaAstxYSnhyswJ76uZPStJRJCTKvosUCJZL5B/0/0)"
         desc = parse_descriptor(d)