CVE-2026-8204

Published: Mag 21, 2026 Last Modified: Mag 21, 2026
ExploitDB:
Other exploit source:
Google Dorks:
MEDIUM 6,3
Source: ff5b8ace-8b95-4078-9743-eac1ca5451de
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Confidentiality: N/A
Integrity: N/A
Availability: N/A

Description

AI Translation Available

Concrete CMS 9.5.0 and below is vulnerable to authorization Bypass in the Calendar Event Frontend Dialog which can allow cross-calendar data disclosure. A public calendar block can be used as a pivot point to access private calendar data. 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 Winston Crooker for reporting.

639

Authorization Bypass Through User-Controlled Key

Incomplete
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Access Control
Potential Impacts:
Bypass Protection Mechanism Gain Privileges Or Assume Identity
Applicable Platforms
All platforms may be affected
Likelihood of Exploit: High
View CWE Details
https://documentation.concretecms.org/9-x/developers/introd…
https://documentation.concretecms.org/9-x/developers/introduction/version-histo…