diff --git a/stdnum/iso6346.py b/stdnum/iso6346.py
index c7edf347..fbaf4c6d 100644
--- a/stdnum/iso6346.py
+++ b/stdnum/iso6346.py
@@ -48,7 +48,7 @@
 from stdnum.util import clean
 
 
-_iso6346_re = re.compile(r'^\w{3}(U|J|Z|R)\d{7}$')
+_iso6346_re = re.compile(r'^[A-Z]{3}(U|J|Z|R)[0-9]{7}$')
 
 
 def compact(number: str) -> str:
diff --git a/stdnum/pt/cc.py b/stdnum/pt/cc.py
index f98f40eb..a0ef4a09 100644
--- a/stdnum/pt/cc.py
+++ b/stdnum/pt/cc.py
@@ -48,7 +48,7 @@
 from stdnum.util import clean
 
 
-_cc_re = re.compile(r'^\d*[A-Z0-9]{2}\d$')
+_cc_re = re.compile(r'^[0-9]*[A-Z0-9]{2}[0-9]$')
 
 
 def compact(number: str) -> str:
diff --git a/tests/test_iso6346.doctest b/tests/test_iso6346.doctest
index d8758167..feee81a5 100644
--- a/tests/test_iso6346.doctest
+++ b/tests/test_iso6346.doctest
@@ -57,3 +57,18 @@ False
 Traceback (most recent call last):
     ...
 InvalidFormat: ...
+
+
+Letters and digits outside of the ASCII range are not valid and should be
+rejected with a validation error instead of crashing.
+
+>>> iso6346.is_valid('CSQU٣054383')
+False
+>>> iso6346.is_valid('CSÉU3054383')
+False
+>>> iso6346.is_valid('CS_U3054383')
+False
+>>> iso6346.validate('CSQU٣054383')
+Traceback (most recent call last):
+    ...
+InvalidFormat: ...
diff --git a/tests/test_pt_cc.doctest b/tests/test_pt_cc.doctest
index 65e4f060..5c26bce6 100644
--- a/tests/test_pt_cc.doctest
+++ b/tests/test_pt_cc.doctest
@@ -34,3 +34,16 @@ These have been found online and should all be valid numbers.
 ... '''
 >>> [x for x in numbers.splitlines() if x and not cc.is_valid(x)]
 []
+
+
+Non-ASCII digits are not valid and should be rejected with a validation
+error instead of crashing.
+
+>>> cc.is_valid('00000000 ٠ ZZ4')
+False
+>>> cc.is_valid('٠٠٠٠٠٠٠٠٠ZZ4')
+False
+>>> cc.validate('00000000 ٠ ZZ4')
+Traceback (most recent call last):
+    ...
+InvalidFormat: ...