CVE-2026-55830: high-severity vulnerability in zopefoundation RestrictedPython
RestrictedPython guard hooks can be shadowed via positional-only arguments
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.3epss 0.3%
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.
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:L
Affected products
zopefoundation · RestrictedPythonRelated CVEs — zopefoundation RestrictedPython
In the same product, most dangerous first.
CVE-2023-37271HIGHRestrictedPython vulnerable to arbitrary code execution via stack frame sandbox escapeEPSS 0.8%CVE-2024-47532HIGHRestrictedPython information leakage via `AttributeError.obj` and the `string` moduleEPSS 0.7%CVE-2023-41039HIGHSandbox escape via various forms of "format" in RestrictedPythonEPSS 0.7%CVE-2026-76825HIGHRestrictedPython: Sandbox escape via string.Formatter field resolutionEPSS 0.6%CVE-2025-22153HIGHtry/except* clauses could allow bypass RestrictedPython via type confusion bug in the CPython interpreterEPSS 0.4%