# CVE-2023-37271: RestrictedPython vulnerable to arbitrary code execution via stack frame sandbox escape

Source: https://junglewise.ai/threats/cve-2023-37271-restrictedpython-vulnerable-to-arbitrary-code-execution-via-stack  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2023-07-11  
License: CC BY 4.0 with a link back

CVE-2023-37271 · Severity: low · CVSS 3.1 · Published 2023-07-11

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.

Technologies: [restrictedpython (PyPI)](https://junglewise.ai/threats/technologies/pypi-restrictedpython). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2023-37271 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2023-37271 being exploited in the wild.

**How severe is CVE-2023-37271?** Low severity, with a CVSS score of 3.1, published 11 July 2023.

**Which products and versions are affected?** restrictedpython (PyPI) ECOSYSTEM:introduced=0,fixed=5.3, GIT:introduced=0,fixed=c8eca66ae49081f0016d2e1f094c3d72095ef531|ECOSYSTEM:introduced=0,fixed=5.3.

**Is there a fix for CVE-2023-37271?** Yes. restrictedpython (PyPI): upgrade to 5.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2023-37271?** Check whether you run restrictedpython (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- restrictedpython (PyPI): upgrade to 5.3 or later

  ```sh
  pip install "restrictedpython>=5.3"
  ```


## Affected products

- restrictedpython (PyPI) ECOSYSTEM:introduced=0,fixed=5.3, GIT:introduced=0,fixed=c8eca66ae49081f0016d2e1f094c3d72095ef531|ECOSYSTEM:introduced=0,fixed=5.3

## Identifiers

- CVE-2023-37271
- GHSA-wqc8-x2pr-7jqh
- PYSEC-2023-118

## Related threats

- [RestrictedPython sandbox escape via string.Formatter field resolution](https://junglewise.ai/threats/cve-2026-76825-restrictedpython-sandbox-escape-via-string-formatter-field)
- [Zope RestrictedPython access policy bypass via positional-only arguments](https://junglewise.ai/threats/cve-2026-55830-zope-restrictedpython-access-policy-bypass-via-positional-only)
- [PYSEC-2026-1874 - try/except* clauses could allow bypass RestrictedPython via type confusion bug in the CPython interpreter](https://junglewise.ai/threats/cve-2025-22153-try-except-clauses-could-allow-bypass-restrictedpython-via-type)
- [RestrictedPython information leakage via `AttributeError.obj` and the `string` module](https://junglewise.ai/threats/cve-2024-47532-restrictedpython-information-leakage-via-attributeerror-obj-and)
- [Sandbox escape via various forms of "format".](https://junglewise.ai/threats/cve-2023-41039-sandbox-escape-via-various-forms-of-format)