Release Date: Sept. 6, 2024

This is the sixth maintenance release of Python 3.12

Python 3.12 is the newest major release of the Python programming language, and it contains many new features and optimizations. 3.12.6 is the latest maintenance release, containing about 90 bugfixes, build improvements and documentation changes since 3.12.5. This is an expedited release to address the following security issues:

• gh-123678 and gh-116741: Upgrade bundled libexpat to 2.6.3 to fix CVE-2024-28757, CVE-2024-45490, CVE-2024-45491 and CVE-2024-45492.
• gh-123067: Fix quadratic complexity in parsing "-quoted cookie values with backslashes by http.cookies. Fixes CVE-2024-7592.
• gh-121285: Remove backtracking from tarfile header parsing for hdrcharset, PAX, and GNU sparse headers. That’s CVE-2024-6232.
• gh-102988: email.utils.getaddresses() and email.utils.parseaddr() now return ('', '') 2-tuples in more situations where invalid email addresses are encountered instead of potentially inaccurate values. Add optional strict parameter to these two functions: use strict=False to get the old behavior, accept malformed inputs. getattr(email.utils, 'supports_strict_parsing', False) can be use to check if the strict paramater is available. This improves the CVE-2023-27043 fix.
• gh-123270: Sanitize names in zipfile.Path to avoid infinite loops (gh-122905) without breaking contents using legitimate characters. That’s CVE-2024-8088.

Also, as mentioned in the previous release of 3.12, this release drops support for macOS versions 10.9 through 10.12. Versions of macOS older than 10.13 haven't been supported by Apple since 2019, and maintaining support for them has become too difficult. (All versions of Python 3.13 have already dropped support for them.)

Major new features of the 3.12 series, compared to 3.11

New features

• More flexible f-string parsing, allowing many things previously disallowed (PEP 701).
• Support for the buffer protocol in Python code (PEP 688).
• A new debugging/profiling API (PEP 669).
• Support for isolated subinterpreters with separate Global Interpreter Locks (PEP 684).
• Even more improved error messages. More exceptions potentially caused by typos now make suggestions to the user.
• Support for the Linux perf profiler to report Python function names in traces.
• Many large and small performance improvements (like PEP 709 and support for the BOLT binary optimizer), delivering an estimated 5% overall performance improvement.

Type annotations

• New type annotation syntax for generic classes (PEP 695).
• New override decorator for methods (PEP 698).

Deprecations

• The deprecated wstr and wstr_length members of the C implementation of unicode objects were removed, per PEP 623.
• In the unittest module, a number of long deprecated methods and classes were removed. (They had been deprecated since Python 3.1 or 3.2).
• The deprecated smtpd and distutils modules have been removed (see PEP 594 and PEP 632. The setuptools package continues to provide the distutils module.
• A number of other old, broken and deprecated functions, classes and methods have been removed.
• Invalid backslash escape sequences in strings now warn with SyntaxWarning instead of DeprecationWarning, making them more visible. (They will become syntax errors in the future.)
• The internal representation of integers has changed in preparation for performance enhancements. (This should not affect most users as it is an internal detail, but it may cause problems for Cython-generated code.)

For more details on the changes to Python 3.12, see What's new in Python 3.12.

More resources

• Online Documentation.
• PEP 693, the Python 3.12 Release Schedule.
• Report bugs via GitHub Issues.
• Help fund Python directly or via GitHub Sponsors, and support the Python community.

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