{"id":"CVE-2021-32807","aliases":["GHSA-qcx9-j53g-ccgf","CVE-2021-32811","GHSA-g4gq-j4p2-j8fr","PYSEC-2021-335","PYSEC-2021-368","PYSEC-2021-370","PYSEC-2021-875"],"title":"Remote Code Execution via unsafe classes in otherwise permitted modules","summary":"Remote Code Execution via unsafe classes in otherwise permitted modules","severity":"medium","cvss":4.4,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N","vendor":"accesscontrol","product":"accesscontrol","ecosystem":"pip","affected":["accesscontrol >= 4.0, < 4.3","accesscontrol >= 5.0, < 5.2","zope >= 4.0, < 4.3","zope >= 5.0, < 5.2"],"patched":["accesscontrol 4.3","accesscontrol 5.2","zope 4.3","zope 5.2"],"published":"2021-08-05","updated":"2026-07-08","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GHSA-qcx9-j53g-ccgf","references":[{"url":"https://github.com/zopefoundation/AccessControl/security/advisories/GHSA-qcx9-j53g-ccgf"},{"url":"https://github.com/zopefoundation/Zope/security/advisories/GHSA-g4gq-j4p2-j8fr"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-32807"},{"url":"https://github.com/zopefoundation/AccessControl/commit/ae2dab0cc34e6dd1561c5b12d4a56cd140f87e1d"},{"url":"https://github.com/zopefoundation/AccessControl/commit/b42dd4badf803bb9fb71ac34cd9cb0c249262f2c"},{"url":"https://github.com/zopefoundation/Zope/commit/869f947e586517566509e0ccdd4d99b60704cc02"},{"url":"https://github.com/zopefoundation/Zope/commit/f72a18dda8e9bf2aedb46168761668464a4be988"},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/accesscontrol/PYSEC-2021-335.yaml"},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/accesscontrol/PYSEC-2021-370.yaml"},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/zope/PYSEC-2021-368.yaml"},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/zope/PYSEC-2021-875.yaml"},{"url":"https://github.com/zopefoundation/AccessControl"},{"url":"https://github.com/zopefoundation/AccessControl/blob/master/CHANGES.rst#51-2021-07-30"}],"tags":["osv","pip"],"epss":0.02049,"epssPercentile":0.80401,"ingestedAt":"2026-07-08T18:25:52.402Z","slug":"CVE-2021-32807","body":"## Overview\n\n### Impact\nThe module `AccessControl` defines security policies for Python code used in restricted code within Zope applications. Restricted code is any code that resides in Zope's object database, such as the contents of `Script (Python)` objects. \n\nThe policies defined in `AccessControl` severely restrict access to Python modules and only exempt a few that are deemed safe, such as Python's `string` module. However, full access to the `string` module also allows access to the class `Formatter`, which can be overridden and extended within `Script (Python)` in a way that provides access to other unsafe Python libraries. Those unsafe Python libraries can be used for remote code execution.\n\nBy default, you need to have the admin-level Zope \"Manager\" role to add or edit `Script (Python)` objects through the web. Only sites that allow untrusted users to add/edit these scripts through the web - which would be a very unusual configuration to begin with - are at risk.\n\n### Patches\nThe problem has been fixed in AccessControl 4.3 and 5.2.\nOnly AccessControl versions 4 and 5 are vulnerable, and only on Python 3, not Python 2.7.\n\n### Workarounds\nA site administrator can restrict adding/editing `Script (Python)` objects through the web using the standard Zope user/role permission mechanisms. Untrusted users should not be assigned the Zope Manager role and adding/editing these scripts through the web should be restricted to trusted users only. This is the default configuration in Zope.\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in the [AccessControl issue tracker](https://github.com/zopefoundation/AccessControl/issues)\n* Email us at [security@plone.org](mailto:security@plone.org)\n\n## Affected packages\n\n- `accesscontrol >= 4.0, < 4.3`\n- `accesscontrol >= 5.0, < 5.2`\n- `zope >= 4.0, < 4.3`\n- `zope >= 5.0, < 5.2`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `accesscontrol 4.3`\n- `accesscontrol 5.2`\n- `zope 4.3`\n- `zope 5.2`","depth":"sunlit","depthScore":25,"depthScoreParts":{"impact":24.2,"likelihood":0.4,"exploitation":0,"ransomware":0},"changes":[]}