{"id":"CVE-2026-55830","aliases":["GHSA-ffg3-p8fm-mjx2"],"url":"https://o3.security/vulnerability/CVE-2026-55830","summary":"RestrictedPython guard hooks can be shadowed via positional-only arguments","details":"RestrictedPython is a tool that helps to define a subset of the Python language which allows to provide a program input into a trusted environment. Prior to 8.3, check_function_argument_names() rejected protected guard hook names for regular, variadic, and keyword-only arguments but omitted positional-only arguments, allowing __getattr__, _getitem_, _write_, or _print_ to be shadowed by a local parameter and bypass the embedding application's access policy. This issue is fixed in version 8.3.","published":"2026-07-08T21:16:36.200Z","modified":"2026-08-31T04:40:57.213317923Z","cvss":{"score":8.3,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"PyPI","name":"restrictedpython","fixedVersion":"8.3"}],"fix":{"url":"https://github.com/zopefoundation/RestrictedPython/commit/3737596ec9f28c34a073cc845bd2f4c0a80cb671","label":"zopefoundation/RestrictedPython@3737596"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55830.json"},{"type":"ADVISORY","url":"https://github.com/zopefoundation/RestrictedPython/security/advisories/GHSA-ffg3-p8fm-mjx2"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55830"},{"type":"FIX","url":"https://github.com/zopefoundation/RestrictedPython/commit/3737596ec9f28c34a073cc845bd2f4c0a80cb671"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-31T04:40:57.213317923Z"}}