Python 3.13.1 Released November 2025 Info

A critical CVE was announced—a use-after-free in the new biased reference counter, only triggerable when mixing subinterpreters and C extensions that manually manipulated PyObject* refcounts. The entire Python security team held an emergency sprint.

Elena sat in her apartment, the snow falling outside, watching a livestream of PyCon India 2025. A teenager from Bangalore named Kavya was demonstrating how she used Python 3.13.1’s JIT to train a small LLM on a Raspberry Pi 6. The JIT compiled the hot training loops into native machine code on the fly, cutting training time from two days to six hours. python 3.13.1 released november 2025

Until November 2025.

Elena laughed out loud. The sound echoed off the empty office walls. A critical CVE was announced—a use-after-free in the

She wrote: “We don’t go backward. We patch forward. The GIL was a beautiful constraint for three decades. But we are not constraint-driven anymore. We are capability-driven. Fix the refcount, add the atomic operations, and ship 3.13.2 by Friday.” A teenager from Bangalore named Kavya was demonstrating

results = [f.result() for f in futures] # True parallelism, no GIL handoff