Open
Description
During fuzzing of Python standard libraries, the following code snippet causes an UnboundLocalError with the following message: UnboundLocalError: cannot access local variable 'pos' where it is not associated with a value'. This occurs in the _get_ptext_to_endchars function at line 1035 in email/_header_value_parser.py.
import email._header_value_parser
email._header_value_parser.parse_message_id("<T@[")
Exception Trace
Traceback (most recent call last):
File "/usr/lib/python3.12/email/_header_value_parser.py", line 2118, in get_msg_id
token, value = get_dot_atom_text(value)
^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.12/email/_header_value_parser.py", line 1344, in get_dot_atom_text
raise errors.HeaderParseError("expected atom at a start of "
email.errors.HeaderParseError: expected atom at a start of dot-atom-text but found '['
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "rep.py", line 2, in <module>
email._header_value_parser.parse_message_id("<T@[")
File "/usr/lib/python3.12/email/_header_value_parser.py", line 2149, in parse_message_id
token, value = get_msg_id(value)
^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.12/email/_header_value_parser.py", line 2121, in get_msg_id
token, value = get_no_fold_literal(value)
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.12/email/_header_value_parser.py", line 2066, in get_no_fold_literal
token, value = get_dtext(value)
^^^^^^^^^^^^^^^^
File "/usr/lib/python3.12/email/_header_value_parser.py", line 1557, in get_dtext
ptext, value, had_qp = _get_ptext_to_endchars(value, '[]')
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.12/email/_header_value_parser.py", line 1033, in _get_ptext_to_endchars
pos = pos + 1
^^^
UnboundLocalError: cannot access local variable 'pos' where it is not associated with a value
CPython versions tested on:
3.12, 3.11, 3.10, 3.9
Operating systems tested on:
Linux