Migration Toolkit for Applications 8: Ansible-core: ansible-core: ansible-galaxy collection install symlink path escape allows arbitrary file write / code execution

A flaw was found in ansible-core. When installing a collection with ansible-galaxy collection install, the archive extractor validates member paths using lexical path normalisation (os.path.abspath) instead of resolving symbolic links (os.path.realpath), and it performs no containment check on symlink-typed directory members before creating them. A crafted collection tarball can chain symlink directory entries so that a subsequent file member is written outside the intended destination directory. This allows an attacker who can get a victim to install a malicious collection to overwrite arbitrary files with the privileges of the user running ansible-galaxy, leading to code execution on the control node. This is a bypass of the fix for CVE-2020-10691.