Release date: Sept. 30, 2026

This is the sixteenth maintenance release of Python 3.13

Note: This is Python 3.13.16, a maintenance release for Python 3.13. Python 3.14 is now the latest feature release series of Python 3. Get the latest release of 3.14.x here.

Python 3.13.16 is the sixteenth maintenance release of 3.13, and the last full maintenance release. Subsequent releases of 3.13 will be security-fixes only. This last maintenance release contains around 290 bugfixes, build improvements and documentation changes since 3.13.15.

Security content in this release

• CVE-2026-19445 gh-156293 Use-after-free of a server-side SSLContext when sni_callback switches contexts

• CVE-2026-19553 gh-156793 SSLContext.wrap_bio() missing validation of server_hostname parameter

• CVE-2026-82049 gh-157190 tarfile extraction filters allow file modification and content disclosure via hard link to symlink

• CVE-2026-15310 gh-156002 Memory exhaustion in zipfile in bzip2/LZMA/Zstandard decompression

• CVE-2026-19672 gh-155999 tarfile extraction filter bypass allows creation of directories outside the destination

• CVE-2026-15806 gh-155694 urllib.request.HTTPPasswordMgr credentials for one URL scheme sent over another scheme

• CVE-2026-17084 gh-155292 StringPrep algorithm considered Unicode codepoint attributes outside Unicode 3.2.0

• gh-158446 Reject float format precision near INT_MAX

• gh-157953 Update bundled Expat to 2.8.5

• gh-158010 Update bundled OpenSSL to 3.5.9 for Windows, macOS and Android, a jump from 3.0.21 to the 3.5 LTS series

• CVE-2026-87910 gh-157265 tarfile hardlink fallback ignores custom extraction filter rejection via None

Major new features of the 3.13 series, compared to 3.12

Some of the new major new features and changes in Python 3.13 are:

New features

• A new and improved interactive interpreter, based on PyPy's, featuring multi-line editing and color support, as well as colorized exception tracebacks.
• An experimental free-threaded build mode, which disables the Global Interpreter Lock, allowing threads to run more concurrently. The build mode is available as an experimental feature in the Windows and macOS installers as well.
• A preliminary, experimental JIT, providing the ground work for significant performance improvements.
• The locals() builtin function (and its C equivalent) now has well-defined semantics when mutating the returned mapping, which allows debuggers to operate more consistently.
• A modified version of mimalloc is now included, optional but enabled by default if supported by the platform, and required for the free-threaded build mode.
• Docstrings now have their leading indentation stripped, reducing memory use and the size of .pyc files. (Most tools handling docstrings already strip leading indentation.)
• The dbm module has a new dbm.sqlite3 backend that is used by default when creating new files.
• The minimum supported macOS version was changed from 10.9 to 10.13 (High Sierra). Older macOS versions will not be supported going forward.
• WASI is now a Tier 2 supported platform. Emscripten is no longer an officially supported platform (but Pyodide continues to support Emscripten).
• iOS is now a Tier 3 supported platform.
• Android is now a Tier 3 supported platform.

Typing

• Support for type defaults in type parameters.
• A new type narrowing annotation, typing.TypeIs.
• A new annotation for read-only items in TypeDicts.
• A new annotation for marking deprecations in the type system.

Removals and new deprecations

• PEP 594 (Removing dead batteries from the standard library) scheduled removals of many deprecated modules: aifc, audioop, chunk, cgi, cgitb, crypt, imghdr, mailcap, msilib, nis, nntplib, ossaudiodev, pipes, sndhdr, spwd, sunau, telnetlib, uu, xdrlib, lib2to3.
• Many other removals of deprecated classes, functions and methods in various standard library modules.
• C API removals and deprecations. (Some removals present in alpha 1 were reverted in alpha 2, as the removals were deemed too disruptive at this time.)
• New deprecations, most of which are scheduled for removal from Python 3.15 or 3.16.

For more details on the changes to Python 3.13, see What's new in Python 3.13.

More resources

• Online Documentation
• PEP 719, 3.13 Release Schedule
• Report bugs at https://github.com/python/cpython/issues.
• Help fund Python directly (or via GitHub Sponsors), and support the Python community.

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