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

Vulnerability summary

CVE-2026-53940 is a high (CVSS 8.8) Path Traversal vulnerability in conda. EPSS estimates a 0.55% chance of exploitation in the next 30 days, higher than 45% of scored vulnerabilities.

Timeline

1. 21-09-2026
   PublishedVulnerability first disclosed.
2. 21-09-2026
   Last modifiedVulnerability information updated.

Description

Conda is a system-level binary package and environment manager that runs on major operating systems and platforms. Prior to 26.5.2, parse_entry_point_def 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/path_actions.py interpolated that command into target_short_path, and PrefixPathAction.target_full_path joined it to the installation prefix without verifying that the result remained under the intended bin or Scripts directory. create_python_entry_point 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.

• CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
• CWE-73External Control of File Name or PathThe product allows user input to control or influence paths or file names that are used in filesystem operations.