CVE-2026-53940: Conda: Entry-point path traversal in noarch:python install (arbitrary file write) — canonical Python implementation

Conda is a system-level binary package and environment manager that runs on major operating systems and platforms. Prior to 26.5.2, parseentrypointdef in conda/common/path/python.py accepted an unvalidated entry-point command from a noarch:python package's info/link.json metadata. CreatePythonEntryPointAction in conda/core/pathactions.py interpolated that command into targetshortpath, and PrefixPathAction.targetfullpath joined it to the installation prefix without verifying that the result remained under the intended bin or Scripts directory. createpythonentrypoint in conda/gateways/disk/create.py then wrote an executable wrapper to the resulting path. A malicious package could use path separators, traversal segments, or an absolute command path to write outside the prefix or overwrite another in-prefix entry point during default install and environment transactions. Out-of-prefix writes require the target parent directory to exist, while an overwritten entry point can execute attacker-controlled Python when later invoked with the installing user's privileges. This issue is fixed in version 26.5.2.