CVE-2026-55830: Zopefoundation Restrictedpython

High severity, CVSS 8.3. EPSS: 0.4% chance of exploitation in the next 30 days.

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.

Affected products

• Zopefoundation Restrictedpython: before 8.3 (fixed in 8.3)

Published 2026-07-08. Last modified 2026-07-10.