Authorization Bypass Through User-Controlled Key Affecting concrete5/concrete5 package, versions <9.5.1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applicationsSnyk Learn
Learn about Authorization Bypass Through User-Controlled Key vulnerabilities in an interactive lesson.
Start learning- Snyk IDSNYK-PHP-CONCRETE5CONCRETE5-17660456
- published27 Jun 2026
- disclosed22 May 2026
- creditUnknown
Introduced: 22 May 2026
CVE-2026-7886 (opens in a new tab)How to fix?
Upgrade concrete5/concrete5 to version 9.5.1 or higher.
Overview
concrete5/concrete5 is a concrete5 open source CMS.
Affected versions of this package are vulnerable to Authorization Bypass Through User-Controlled Key in the AddMessage and UpdateMessage process via the attachments[] parameter. An attacker can bypass file permission restrictions by referencing file IDs directly, allowing unauthorized access to files managed by the system. This is only exploitable if files are not stored in a private storage location outside of the webroot, where permissions can be enforced on access.
Workaround
This vulnerability can be mitigated by configuring a private storage location for sensitive files outside of the webroot, ensuring permissions are checked on file access.