-------- Forwarded Message -------- Subject: [Security-announce][CVE-2026-19672] tarfile extraction filter bypass allows creation of directories outside the destination Date: Wed, 19 Aug 2026 14:56:06 +0100 From: Stan Ulbrych via Security-announce <[email protected]> Reply-To: [email protected] To: [email protected] CC: Stan Ulbrych <[email protected]> There is a MEDIUM severity vulnerability affecting CPython. The tarfile module's tar and data extraction filters created directories outside the destination for members whose name leaves the destination and returns to it, such as ../evil/../dest/sub/file. The containment check used the resolved path, but intermediate directories were created from the name as given. Only empty directories are created outside the destination. Member contents are still extracted inside it. To return to the destination the member's name must contain the destination directory's own final component, so extraction into a secure randomised directory is not affected. This affects POSIX platforms only. On Windows, .. components are collapsed before the path reaches the filesystem, so the directories outside the destination are never created. Please see the linked CVE ID for the latest information on affected versions: * https://www.cve.org/CVERecord?id=CVE-2026-19672 * https://github.com/python/cpython/pull/156000 _______________________________________________ Security-announce mailing list -- [email protected] https://mail.python.org/mailman3//lists/security-announce.python.org
