Via a type confusion bug in the CPython interpreter when using try/except* RestrictedPython could be bypassed. We believe this should be fixed upstream in Python itself until that we remove support for try/except* from RestrictedPython. (It has been fixed for some Python versions.)
A user can gain access to protected (and potentially sensible) information indirectly via AttributeError.obj and the string module.
RestrictedPython is a restricted execution environment for Python to run untrusted code. Python's "format" functionality allows someone controlling the format string to "read" all objects accessible through recursive attribute lookup and subscription from objects he can access. This can lead to critical information disclosure. With RestrictedPython, the format functionality is available via the format and format_map methods of str (and unicode) (accessed either via the class or its instances) and …
RestrictedPython is a tool that helps to define a subset of the Python language which allows users to provide a program input into a trusted environment. RestrictedPython does not check access to stack frames and their attributes. Stack frames are accessible within at least generators and generator expressions, which are allowed inside RestrictedPython. Prior to versions 6.1 and 5.3, an attacker with access to a RestrictedPython environment can write code …