CVE-2026-8205

Analyzed Analyzed - Analysis Complete

Authorization Bypass in Concrete CMS Calendar Block

Publication date: 2026-05-21

Last updated on: 2026-05-26

Assigner: ConcreteCMS

Description

Concrete CMS 9.5.0 and below is vulnerable to authorization bypass in the Calendar Block since action_get_events does not check canView on the calendar which results in restricted event details being disclosed. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 6.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks lalalala5678 for reporting.

CVSS Scores

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Meta Information

Published

2026-05-21

Last Modified

2026-05-26

Generated

2026-07-02

AI Q&A

2026-05-22

EPSS Evaluated

2026-06-30

NVD

CVE-2026-8205

Affected Vendors & Products

Vendor	Product	Version / Range
concretecms	concrete_cms	to 9.5.0 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-425	The web application does not adequately enforce appropriate authorization on all restricted URLs, scripts, or files.

Attack-Flow Graph

Executive Summary

This vulnerability affects Concrete CMS version 9.5.0 and below. It is an authorization bypass issue in the Calendar Block component. Specifically, the function action_get_events does not properly check whether a user has permission (canView) to access the calendar. As a result, users can access restricted event details that they should not be able to see.

Compliance Impact

The vulnerability in Concrete CMS 9.5.0 and below allows authorization bypass in the Calendar Block, leading to restricted event details being disclosed without proper permission checks.

This unauthorized disclosure of restricted event information could potentially impact compliance with data protection regulations such as GDPR and HIPAA, which require strict controls on access to personal and sensitive information.

However, the provided information does not explicitly state the exact compliance implications or whether the disclosed event details include personal or sensitive data covered by these regulations.

Impact Analysis

The vulnerability can lead to unauthorized disclosure of restricted event details within the Concrete CMS Calendar Block. This means that sensitive or confidential event information could be exposed to users who do not have the proper permissions, potentially leading to privacy breaches or information leakage.

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