The official python 3.14.2 release notes detail a targeted maintenance update shipped on December 5, 2025. This is the second maintenance release of the 3.14 series, containing 18 bugfixes, build improvements, and documentation changes. It is an expedited release primarily to address four critical regressions causing crashes in multiprocessing, dataclasses, dictionary insertion, and regex scanning, and includes two security fixes, one for a quadratic complexity vulnerability (CVE-2025-12084) and one for a potential denial of service in http.server. Users running Python 3.14.0 or 3.14.1 should upgrade to resolve these stability and security issues promptly.

This maintenance release is recommended for all users of Python 3.14.0 or 3.14.1. Upgrade now to patch critical security vulnerabilities and fix regressions that cause program crashes.

What Changed

• Security Fixes: Patched CVE-2025-12084, a quadratic behavior vulnerability in the node ID cache, and a potential virtual memory allocation denial of service in http.server.
• Regression Fixes: Resolved crashes in multiprocessing during upgrades, dataclasses without an __init__ method, dictionary insertion (segmentation faults), and re.Scanner with multiple capturing groups.
• Build Improvements: Official macOS and Windows binaries now include an experimental JIT compiler, and Android binary releases are now available.
• Documentation: Updated documentation for the 3.14 series and its new features.

Why It Matters

• Security Patches: The CVE-2025-12084 fix prevents a potential performance degradation attack, while the http.server patch closes a denial-of-service vector, making your applications more resilient.
• Stability Restored: The four fixed regressions were causing real crashes in production code. This release restores the reliability expected from the 3.14 series.
• Performance & Access: The inclusion of an experimental JIT in official binaries offers a potential performance boost for many users, and Android support expands Python’s reach to mobile development.
• Maintenance Momentum: With 18 total fixes, this release demonstrates active maintenance of the 3.14 series, ensuring a solid foundation for development.

Who Should Upgrade

This release is particularly relevant for DevOps engineers and security teams managing production deployments, as it contains critical security and stability fixes. API developers and end users running applications on Python 3.14.0 or 3.14.1 should also upgrade immediately to prevent crashes related to the fixed regressions in multiprocessing, dataclasses, and regular expressions.

How to Upgrade

1. Review the ‘Incompatible Changes’ and ‘Deprecations’ documentation for Python 3.14.
2. For macOS: Download and run the macOS installer from the official Python website.
3. For Windows: Use the new Python install manager from the Windows Store or download page, or use the traditional installer.
4. For source builds: Download the source tarball, compile, and install.
5. Run your application’s test suite to verify compatibility with the new version.
6. Deploy to a staging environment before rolling out to production.

Usage Examples

• Using template string literals (t-strings) for custom string interpolation, similar to f-string syntax.
• Employing the new compression.zstd module for Zstandard compression and decompression.
• Utilizing the improved C API (PEP 741) for configuring the Python interpreter.
• Leveraging the new command-line interface to inspect running Python processes with asynchronous tasks.

Known Issues

• This release fixes several regressions that could cause crashes or exceptions in running programs.
• Refer to the official ‘Incompatible changes’ and ‘Deprecations’ documentation for the 3.14 series for a full list of breaking changes.

Feature Flow

Official Release Notes

View full release notes on Python.org →