RestrictedPython: Sandbox escape via string.Formatter field resolution
RestrictedPython is a tool that helps define a subset of the Python language for accepting program input in a trusted environment. Prior to 8.4, RestrictedPython could allow a sandbox escape when a custom import policy or globals exposed the standard library string module, the string.Formatter class, a Formatter instance, or a Formatter subclass to restricted code. The string.Formatter methods format, get_field, get_value, and vformat performed attribute and item traversal internally without passing through RestrictedPython's safer_getattr protections. Restricted code could use those live object references to reach function globals, builtins,
RestrictedPython guard hooks can be shadowed via positional-only arguments
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.
try/except* clauses could allow bypass RestrictedPython via type confusion bug in the CPython interpreter
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. Via a type confusion bug in versions of the CPython interpreter starting in 3.11 and prior to 3.13.2 when using `try/except*`, RestrictedPython starting in version 6.0 and prior to version 8.0 could be bypassed. The issue is patched in version 8.0 of RestrictedPython by removing support for `try/except*` clauses. No known workarounds are available.
RestrictedPython information leakage via `AttributeError.obj` and the `string` module
RestrictedPython is a restricted execution environment for Python to run untrusted code. A user can gain access to protected (and potentially sensible) information indirectly via AttributeError.obj and the string module. The problem will be fixed in version 7.3. As a workaround, If the application does not require access to the module string, it can remove it from RestrictedPython.Utilities.utility_builtins or otherwise do not make it available in the restricted execution environment.