CVE-2026-77401
mediumpriority · track · 0EPSS 0.005 · 40 %ileUSEPSS · scored 2026-10-27
Zope AccessControl provides a general security framework for use in Zope. Prior to 7.4, applications that allow untrusted users to create and execute AccessControl-controlled Python code do not safely guard str.format and str.format_map when those methods are reached through a str subclass. In both ImplPython.py and cAccessControl.c, Python formatting can recursively access attributes and subscriptions using unrestricted getattr and getitem behavior instead of the policy-restricted getattr and getitem operations. A controlled format string can therefore disclose objects reachable from values available to the formatting operation. This issue is fixed in version 7.4.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (1)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- GHSA-pq59-9fq7-m886Zope AccessControl vulnerable to information disclosure through Python string `format` and `format_map` functions2026-09-17ghsa · osvUS
### Impact Python's string `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. The `AccessControl` package already guards against direct access to the formatting functions on string instances, but these mitigations did not cover subclasses of `str`. Affected are all users who allow untrusted users to create AccessControl controlled Python code and execute it. ### Patches A fix was published with version 7.4. ### Workarounds There is no workaround.
- PYSEC-2026-4022Zope AccessControl vulnerable to information disclosure through Python string `format` and `format_map` functions2026-10-01vendor · osvUS
### Impact Python's string `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. The `AccessControl` package already guards against direct access to the formatting functions on string instances, but these mitigations did not cover subclasses of `str`. Affected are all users who allow untrusted users to create AccessControl controlled Python code and execute it. ### Patches A fix was published with version 7.4. ### Workarounds There is no workaround.
also known as (2)
Other names and identifiers for this entity.
sources
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references (3) nvd
External citations — patches, advisories, analysis.
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