CVE-2026-77401
Zope AccessControl: Information disclosure through Python string `format` and `format_map` functions
Description
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.
INFO
Published Date :
Sept. 16, 2026, 3:17 p.m.
Last Modified :
Sept. 16, 2026, 3:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-77401
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update Zope AccessControl to version 7.4.
- Apply vendor-provided patches if updating is not possible.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-77401.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-77401 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-77401
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-77401 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-77401 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Sep. 16, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N Added CWE CWE-693 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/77xxx/CVE-2026-77401.json">CVE-2026-77401</a> Added Reference https://github.com/zopefoundation/AccessControl/commit/f980450eea416718be62847f34dfd51822938e43 Added Reference https://github.com/zopefoundation/AccessControl/releases/tag/7.4 Added Reference https://github.com/zopefoundation/AccessControl/security/advisories/GHSA-pq59-9fq7-m886