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.format_map 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 and 6.2.
Workarounds
There are no workarounds.
References
GHSA-xjw2-6jm9-rf67 describes the corresponding problem for RestrictedPython.
d-maurer Remediation developer
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
getattrandgetitem, not the policy restrictedAccessControlvariants_getattr_and_getitem_. This can lead to critical information disclosure.AccessControlalready provides a safe variant forstr.formatand denies access tostring.Formatter. However,str.format_mapis still unsafe.Affected are all users who allow untrusted users to create
AccessControlcontrolled Python code and execute it.Patches
A fix will be introduced in the versions 4.4 and 6.2.
Workarounds
There are no workarounds.
References
GHSA-xjw2-6jm9-rf67 describes the corresponding problem for
RestrictedPython.