CVE-2023-41050: Information disclosure through Python's "format" functionality in Zope AccessControl
Impact Python's "format" functionality allows someone controlling the format string to "read" objects accessible (recursively) via attribute access and subscription from accessible objects. Those attribute accesses and subscriptions use Python's full blown getattr and getitem, not the policy restricted AccessControl variants getattr and getitem. This can lead to critical information disclosure.
AccessControl already provides a safe variant for str.format and denies access to string.Formatter. However, str.formatmap is still unsafe.
Affected are all users who allow untrusted users to create AccessControl controlled Python code and execute it.
Patches A fix will be introduced in the versions 4.4, 5.8 and 6.2.
Workarounds There are no workarounds.
References https://github.com/zopefoundation/RestrictedPython/security/advisories/GHSA-xjw2-6jm9-rf67 describes the corresponding problem for RestrictedPython.
Other sources
AccessControl provides a general security framework for use in Zope. Python's "format" functionality allows someone controlling the format string to "read" objects accessible (recursively) via attribute access and subscription from accessible objects. Those attribute accesses and subscriptions use Python's full blown getattr and getitem, not the policy restricted AccessControl variants getattr and getitem. This can lead to critical information disclosure. AccessControl already provides a safe variant for str.format and denies access to string.Formatter. However, str.formatmap is still unsafe. Affected are all users who allow untrusted users to create AccessControl controlled Python code and execute it. A fix has been introduced in versions 4.4, 5.8 and 6.2. Users are advised to upgrade. There are no known workarounds for this vulnerability.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the impact of CVE-2023-41050?
The vulnerability allows an attacker to read objects accessible via attribute access and subscription from accessible objects.
How does CVE-2023-41050 affect Zope and AccessControl?
Zope versions 4.8.9 and earlier, 5.8.4 and earlier, and 6.2 and earlier are affected. AccessControl versions 4.4 and earlier, 5.8 and earlier, and 6.2 and earlier are also affected.
What is the severity of CVE-2023-41050?
The severity of CVE-2023-41050 is rated as high, with a CVSS score of 7.7.
Are there any remedies or fixes available for CVE-2023-41050?
Yes, updating to Zope 5.8.4 or later, AccessControl 5.8 or later, or AccessControl 6.2 or later will address the vulnerability.
Where can I find more information about CVE-2023-41050?
You can find more information about CVE-2023-41050 at the following references: [GitHub Advisory](https://github.com/zopefoundation/AccessControl/security/advisories/GHSA-8xv7-89vj-q48c), [NVD NIST](https://nvd.nist.gov/vuln/detail/CVE-2023-41050), [GitHub Commit](https://github.com/zopefoundation/AccessControl/commit/6bc32692e0d4b8d5cf64eae3d19de987c7375bc9).