CVE-2021-32811: Remote Code Execution via Script (Python) objects under Python 3

Vulnerability summary

CVE-2021-32811 is a high (CVSS 7.5) vulnerability in zope accesscontrol. EPSS estimates a 2.30% chance of exploitation in the next 30 days, higher than 83.2% of scored vulnerabilities.

Timeline

1. 02-08-2021
   PublishedVulnerability first disclosed.
2. 03-08-2024
   Last modifiedVulnerability information updated.

Description

Zope is an open-source web application server. Zope versions prior to versions 4.6.3 and 5.3 have a remote code execution security issue. In order to be affected, one must use Python 3 for one's Zope deployment, run Zope 4 below version 4.6.3 or Zope 5 below version 5.3, and have the optional `Products.PythonScripts` add-on package installed. By default, one must 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 are at risk. Zope releases 4.6.3 and 5.3 are not vulnerable. As a workaround, a 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.

• CWE-915Improperly Controlled Modification of Dynamically-Determined Object AttributesThe product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified.
• CWE-1321Improperly Controlled Modification of Object Prototype AttributesThe product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.