CVE-2023-37271
HighCVSS 8.4Exploitation Probability (EPSS)
Elevated risk51th percentile - higher than 51% of all known CVEs
Summary
RestrictedPython is a tool that defines a subset of the Python language, allowing users to provide program input into a trusted environment. In versions prior to 6.1 and 5.3, an attacker could access the current stack frame in a generator, allowing them to break out of the RestrictedPython boundaries and potentially execute arbitrary code in the Python interpreter.
Risk Assessment
Organizations that allow untrusted users to write code in the RestrictedPython environment are at serious risk of unauthorized code execution. This is particularly relevant for Zope and Plone deployments where administrators may allow the creation or editing of objects like `Script (Python)`, `DTML Method`, `DTML Document`, or `Zope Page Template`.
Recommendation
It is recommended to upgrade to versions 6.1 or 5.3 to mitigate this vulnerability. Additionally, consider restricting access to the RestrictedPython environment for untrusted users.
Other vulnerabilities in RestrictedPython
See all- CVE-2026-55830High
RestrictedPython before version 8.3 incorrectly validated positional-only argument names, allowing protected hook names (e.g., __getattr__, _getitem_, _write_, _print_) to be shadowed by local parameters. This flaw enables bypassing the embedding application's access policy.
- CVE-2023-41039High
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, which can lead to critical information disclosure.
Original NVD description (English source)
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 that gets the current stack frame in a generator and then walk the stack all the way beyond the RestrictedPython invocation boundary, thus breaking out of the restricted sandbox and potentially allowing arbitrary code execution in the Python interpreter. All RestrictedPython deployments that allow untrusted users to write Python code in the RestrictedPython environment are at risk. In terms of Zope and Plone, this would mean deployments where the administrator allows untrusted users to create and/or edit objects of type `Script (Python)`, `DTML Method`, `DTML Document` or `Zope Page Template`. This is a non-default configuration and likely to be extremely rare. The problem has been fixed in versions 6.1 and 5.3.