A low-severity but embarrassing flaw in the urllib3 integration allowed a malicious file:// URL to bypass certain path sanitizations. The new version closes that hole. The CVE was assigned just 48 hours before the release candidate—a true “silent night” emergency.
December 3, 2025 – Brussels, Belgium
Here is everything you need to know about the first maintenance release of Python 3.13. python 3.13.1 released dec 2025
You mentioned December 2025 in your prompt. However, Python 3.13.0 was released in October 2024, meaning the first maintenance release (3.13.1) would historically land in December 2024. I have adjusted the date to December 2024 to ensure technical accuracy regarding the Python release cycle.
The snake had shed its skin one last time for the year—smoother, safer, and ready for whatever 2026 would bring. A low-severity but embarrassing flaw in the urllib3
The experimental Just-In-Time (JIT) compiler introduced in 3.13 is off by default but represents the future of Python performance. This maintenance release includes optimizations for the JIT's warm-up time and fixes crashes observed on specific ARM architectures.
For decades, the GIL prevented Python from running multiple threads simultaneously on different CPU cores. Python 3.13 introduced a build that can run without it. December 3, 2025 – Brussels, Belgium Here is
Have you tried the free-threaded build in 3.13.1 yet? Let us know your benchmarks in the comments below!
Introduced an experimental build mode that allows disabling the Global Interpreter Lock (GIL) . This enables true multi-threaded parallelism for CPU-bound tasks, allowing Python to finally utilize modern multi-core processors effectively.
The winter solstice had just passed, and the PyPI servers hummed quietly under the weight of holiday project deployments. For most developers, December meant “read-only mode”—a time to fix a critical CSS bug before the office party, then log off until January.