{"id":"CVE-2021-41131","aliases":["GHSA-wjw6-2cqr-j4qr","PYSEC-2021-376"],"url":"https://o3.security/vulnerability/CVE-2021-41131","summary":"Client metadata path-traversal","details":"### Impact\nIn both clients (`tuf/client` and `tuf/ngclient`), there is a path traversal vulnerability that in the worst case can overwrite files ending in `.json` anywhere on the client system on a call to `get_one_valid_targetinfo()`. It occurs because the rolename is used to form the filename, and may contain path traversal characters (ie `../../name.json`).\n\nThe impact is mitigated by a few facts:\n* It only affects implementations that allow arbitrary rolename selection for delegated targets metadata\n* The attack requires the ability to A) insert new metadata for the path-traversing role and B) get the role delegated by an existing targets metadata\n* The written file content is heavily restricted since it needs to be a valid, signed targets file. The file extension is always .json.\n\n### Patches\nA fix is available in version 0.19 or newer.\n\n### Workarounds\nNone that do not require code changes. Clients can restrict the allowed character set for rolenames, or they can store metadata in files named in a way that is not vulnerable: neither of these approaches is possible without modifying python-tuf.\n\n### References\n- [The issue where this was discovered](https://github.com/theupdateframework/python-tuf/issues/1527)\n- [Proof of Concept demonstrating the flaw](https://github.com/jku/path-traversal-poc)\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [python-tuf](https://github.com/theupdateframework/python-tuf/issues)\n* Contact the maintainers by email or Slack\n","published":"2021-10-19T18:15:07.967Z","modified":"2026-08-27T08:15:01.176583Z","cvss":{"score":8.7,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"tuf","fixedVersion":"0.19.0"}],"fix":{"url":"https://github.com/theupdateframework/python-tuf/commit/4ad7ae48fda594b640139c3b7eae21ed5155a102","label":"theupdateframework/python-tuf@4ad7ae4"},"references":[{"type":"ADVISORY","url":"https://github.com/theupdateframework/python-tuf/security/advisories/GHSA-wjw6-2cqr-j4qr"},{"type":"REPORT","url":"https://github.com/theupdateframework/python-tuf/issues/1527"},{"type":"FIX","url":"https://github.com/theupdateframework/python-tuf/commit/4ad7ae48fda594b640139c3b7eae21ed5155a102"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-41131"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/tuf/PYSEC-2021-376.yaml"},{"type":"PACKAGE","url":"https://github.com/theupdateframework/python-tuf"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-27T08:15:01.176583Z"}}