CVE-2026-77401 (CVSS 6.8)

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.

Is your site exposed to CVE-2026-77401?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

6.8

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

Weakness Type (CWE)

CWE-693 CWE-693

References

Other References

https://github.com/zopefoundation/AccessControl/commit/f980450eea416718be62847f34dfd51822938e43 https://github.com/zopefoundation/AccessControl/releases/tag/7.4 https://github.com/zopefoundation/AccessControl/security/advisories/GHSA-pq59-9fq7-m886

Frequently Asked Questions

What is CVE-2026-77401? +

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. It has a CVSS v3.1 base score of 6.8 (MEDIUM).

How severe is CVE-2026-77401? +

CVE-2026-77401 has a CVSS v3.1 score of 6.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2026-77401? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-48033

Hulumi is an open-source toolkit that ships secure-by-default cloud and platform infrastructure components for Pulumi. Prior to version 1.4.0, policy …

CVE-2026-0278

Multiple protection mechanism failures in the Prisma Access Agent Data Loss Prevention (DLP) component for Windows allow a local user …

CVE-2025-3114

Code Execution via Malicious Files: Attackers can create specially crafted files with embedded code that may execute without adequate security …

CVE-2024-51481

Nix is a package manager for Linux and other Unix systems. On macOS, built-in builders (such as `builtin:fetchurl`, exposed to …

CVE-2025-65100

Isar is an integration system for automated root filesystem generation. In versions 0.11-rc1 and 0.11, defining ISAR_APT_SNAPSHOT_DATE alone does not …

CVE-2025-29864

Protection Mechanism Failure vulnerability in ESTsoft ALZip on Windows allows SmartScreen bypass.This issue affects ALZip: from 12.01 before 12.29.

CVE-2026-77401