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TypeError: '<' not supported between instances of 'NoneType' and 'int' raised during call to email.message_from_file #134151

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TypeError: '<' not supported between instances of 'NoneType' and 'int' raised during call to email.message_from_file#134151
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stdlibStandard Library Python modules in the Lib/ directorytopic-emailtype-bugAn unexpected behavior, bug, or error

Description

@gabe-sherman
gabe-sherman
opened on May 17, 2025

Bug report

Bug description:

During fuzzing of Python standard libraries, the following code snippet causes a TypeError with the following message: TypeError: '<' not supported between instances of 'NoneType' and 'int'. This occurs in the decode_params function at line 419 in email/utils.py.

import sys
import io
import email
d =  io.StringIO(open(sys.argv[1], "r").read())
email.message_from_file(d)

POC File:

https://github.com/FuturesLab/POC/blob/main/py-email/poc-02

Exception Trace

Traceback (most recent call last):
  File "rep.py", line 5, in <module>
    email.message_from_file(d)
  File "/usr/lib/python3.12/email/__init__.py", line 53, in message_from_file
    return Parser(*args, **kws).parse(fp)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/email/parser.py", line 54, in parse
    return feedparser.close()
           ^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/email/feedparser.py", line 185, in close
    self._call_parse()
  File "/usr/lib/python3.12/email/feedparser.py", line 178, in _call_parse
    self._parse()
  File "/usr/lib/python3.12/email/feedparser.py", line 304, in _parsegen
    boundary = self._cur.get_boundary()
               ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/email/message.py", line 861, in get_boundary
    boundary = self.get_param('boundary', missing)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/email/message.py", line 725, in get_param
    for k, v in self._get_params_preserve(failobj, header):
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/email/message.py", line 674, in _get_params_preserve
    params = utils.decode_params(params)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/email/utils.py", line 419, in decode_params
    continuations.sort()
TypeError: '<' not supported between instances of 'NoneType' and 'int'

CPython versions tested on:

3.12, 3.11, 3.10, 3.9

Operating systems tested on:

Linux

Linked PRs

Activity

  1. gabe-sherman
    added
    type-bugAn unexpected behavior, bug, or error
    on May 17, 2025
  2. picnixz
    added
    stdlibStandard Library Python modules in the Lib/ directory
    topic-email
    on May 17, 2025

  3. picnixz commented on May 18, 2025

    @picnixz
    picnixz
    on May 18, 2025
    Member

    @bitdancer If possilbe, could you also have a look at:

    TiA.

  4. bitdancer commented on May 18, 2025

    @bitdancer
    bitdancer
    on May 18, 2025
    Member

    This issue is in the old code, not the new API. If someone feels like fixing it I'll review, but I'm not going to fix this one myself. I'll look at the other issues presently, which are in the new API.

  5. zangjiucheng commented on May 26, 2025

    @zangjiucheng
    zangjiucheng
    on May 26, 2025
    Contributor

    Hello everyone,

    I am surprised to discover that this is a legend code craft from 17 years ago. I am uncertain of the extent to which it could be beneficial to fix it, as we have already received a new API. However, I would appreciate it if you could take a look at it, @bitdancer.

    Please let me know if you believe it is appropriate to merge this into the main branch :), thanks!

  6. picnixz
    added a commit that references this issue on Jun 8, 2025

    gh-134151 Fix `TypeError` in `email.utils.decode_params` when sorting…

    bcb6b45
  7. miss-islington
    added 2 commits that reference this issue on Jun 8, 2025

    pythongh-134151 Fix `TypeError` in `email.utils.decode_params` when s…

    be338b2

    pythongh-134151 Fix `TypeError` in `email.utils.decode_params` when s…

    b346f6d
  8. picnixz
    added 2 commits that reference this issue on Jun 8, 2025

    [3.13] gh-134151 Fix `TypeError` in `email.utils.decode_params` when …

    e5d1771

    [3.14] gh-134151 Fix `TypeError` in `email.utils.decode_params` when …

    85efa77

  9. bitdancer commented on Jun 8, 2025

    @bitdancer
    bitdancer
    on Jun 8, 2025
    Member

    Thanks @zangjiucheng for the fix, and @picnixz for the additional review and merge.

  10. bitdancer
    closed this as completedon Jun 8, 2025
  11. lkollar
    added a commit that references this issue on Jun 19, 2025

    pythongh-134151 Fix `TypeError` in `email.utils.decode_params` when s…

    a45c031
  12. Pranjal095
    added a commit that references this issue on Jul 12, 2025

    pythongh-134151 Fix `TypeError` in `email.utils.decode_params` when s…

    b9a524f
  13. taegyunkim
    added a commit that references this issue on Aug 4, 2025

    pythongh-134151 Fix `TypeError` in `email.utils.decode_params` when s…

    e1147e4
  14. Agent-Hellboy
    added a commit that references this issue on Aug 19, 2025

    pythongh-134151 Fix `TypeError` in `email.utils.decode_params` when s…

    26e9fc5
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