python.org API flaw exposed Python release metadata to admin-level forgery

The Python Software Foundation disclosed a critical authentication bypass in the python.org release management API that could have let attackers forge administrator-level requests and modify Python release metadata. The flaw, reported by Splitline Ng of DEVCORE and confirmed by the Python Security Response Team, could have enabled changes to download and verification URLs for official Python installers, creating a path to distribute tampered files through trusted python.org infrastructure. The vulnerable logic reportedly dated back to 2014, affecting the release pipeline for more than a decade, but maintainers said post-incident forensics found no evidence of exploitation.

The PSF patched the issue rapidly, with production fixes deployed within 24 hours and broader remediation completed within 48 hours, while also disabling risky API behavior and tightening release controls. Additional hardening included stricter URL validation, mandatory HTTPS enforcement, negative authentication test coverage, longer log retention, and stronger provenance measures around release artifacts, including emphasis on Sigstore alongside existing PGP signing. A subsequent Trail of Bits review funded by OpenAI reportedly found no additional authentication or authorization flaws, and the Foundation said the changes were designed to reduce the risk of unauthorized modification of Python downloads distributed via official channels.