HIGH 8.3 GitHub
CVE-2026-55830
RestrictedPython guard hooks can be shadowed via positional-only arguments
### Impact
RestrictedPython rewrites sensitive operations to go through guard hooks. Attribute access becomes `_getattr_(obj, name)`, item access becomes `_getitem_(obj, key)`, writes go through `_write_`, and print goes through `_print_`. The embedding application supplies these hooks to enforce its policy.
Argument-name validation rejects these protected names for regular arguments, `*args`, `**kwargs`, and keyword-only arguments, but it misses positional-only arguments (the ones before `/`)
Affected Products
- pip/RestrictedPython <= 8.2
References
- https://github.com/advisories/GHSA-ffg3-p8fm-mjx2
- https://github.com/zopefoundation/RestrictedPython/security/advisories/GHSA-ffg3-p8fm-mjx2
- https://nvd.nist.gov/vuln/detail/CVE-2026-55830
- https://github.com/zopefoundation/RestrictedPython/commit/3737596ec9f28c34a073cc845bd2f4c0
This high severity vulnerability with a CVSS score of 8.3 was published on 2026-08-28 via GitHub. Affected: pip/RestrictedPython <= 8.2.
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