GHSA-f42x-p2mx-hm8r: Penelope unsafe tar extraction allows arbitrary local file write via crafted session archive

Summary Penelope versions prior to 0.19.3 extracted tar archives received from remote sessions without validating archive member paths. When using the affected Unix download path, a malicious or compromised remote session could return a crafted tar archive containing path traversal entries, such as ../, causing files to be written outside the intended download directory on the Penelope operator's machine. The impact is limited to files writable by the user running Penelope. In some cases, this arbitrary file write could be chained to operator-side code execution if the attacker can overwrite a file that Penelope or the user later executes, such as ~/.penelope/peneloperc. The issue has been fixed in version 0.19.3 by rejecting unsafe archive paths during extraction. Affected conditions The issue requires the operator to use the Main Menu download command to download files from a malicious or compromised remote session that can influence the tar archive returned to Penelope. The Python agent download path is not affected in the same way because it does not rely on the remote tar command. The vulnerable behavior is related to Python's historical tarfile extraction defaults. In Python versions before 3.14, TarFile.extractall() did not use the safer data extraction filter by default, so applications extracting untrusted tar archives needed to explicitly provide a safe extraction filter or perform their own path validation. Python 3.14 changes the default extraction behavior to use the data filter, which rejects dangerous archive features such as absolute paths and paths outside the destination directory. Penelope 0.19.3 now performs explicit validation/rejection of unsafe archive paths so the fix does not depend on the Python runtime version. Details The vulnerable code is in the Unix download() implementation. Penelope creates a local download directory: local_download_folder = self.directory / "downloads" Later, it opens a tar archive received from the remot