CVE-2026-8428

Published: Mag 21, 2026 Last Modified: Mag 21, 2026
ExploitDB:
Other exploit source:
Google Dorks:
HIGH 7,5
Source: ff5b8ace-8b95-4078-9743-eac1ca5451de
Attack Vector: network
Attack Complexity: high
Privileges Required: none
User Interaction: active
Confidentiality: N/A
Integrity: N/A
Availability: N/A

Description

AI Translation Available

Concrete CMS 9.5.0 and below emits a CSRF token in the local_available_update.php view ($token->output('do_update')) but the corresponding do_update() method in concrete/controllers/single_page/dashboard/system/update/update.php never calls $this->token->validate('do_update'). The form is rendered as a POST form, meaning the token reaches the browser, but because the controller discards it without verification, an attacker can craft a cross-site POST that triggers a core CMS update to an attacker-specified version string.  In order to be vulnerable, theictim must be passing canUpgrade()anda valid update version must be present under DIR_CORE_UPDATES. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks https://github.com/maru1009 for reporting.

352

Cross-Site Request Forgery (CSRF)

Stable
Abstraction: Compound Structure: Composite
Common Consequences
Security Scopes Affected:
Confidentiality Integrity Availability Non-Repudiation Access Control
Potential Impacts:
Gain Privileges Or Assume Identity Bypass Protection Mechanism Read Application Data Modify Application Data Dos: Crash, Exit, Or Restart
Applicable Platforms
Technologies: Web Based, Web Server
Likelihood of Exploit: Medium
View CWE Details
829

Inclusion of Functionality from Untrusted Control Sphere

Incomplete
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Confidentiality Integrity Availability
Potential Impacts:
Execute Unauthorized Code Or Commands
Applicable Platforms
All platforms may be affected
View CWE Details
https://documentation.concretecms.org/9-x/developers/introd…
https://documentation.concretecms.org/9-x/developers/introduction/version-histo…