Concrete CMS up to 9.5.2 Form Block legacy.php cross site scripting

Summaryinfo

A vulnerability, which was classified as problematic, was found in Concrete CMS up to 9.5.2. The impacted element is an unknown function of the file concrete/single_pages/dashboard/reports/forms/legacy.php of the component Form Block. Such manipulation leads to cross site scripting. This vulnerability is listed as CVE-2026-81896. The attack may be performed from remote. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Concrete CMS up to 9.5.2. It has been rated as problematic. Affected by this issue is some unknown functionality of the file concrete/single_pages/dashboard/reports/forms/legacy.php of the component Form Block. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. CVE summarizes:

Concrete CMS before 9.5.3 does not apply HTML entity encoding to user-defined Form block question labels when rendering them as column headers in the Dashboard Form Submissions report (concrete/single_pages/dashboard/reports/forms/legacy.php). a rogue editor could store markup or script in a label that then executes in the browser of any administrator who opens the submissions report for the affected form, producing stored cross-site scripting in the Dashboard. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 8.4 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.

The advisory is available at documentation.concretecms.org. This vulnerability is handled as CVE-2026-81896 since 08/27/2026. The exploitation is known to be easy. The attack may be launched remotely. Additional levels of successful authentication are necessary for exploitation. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1059.007 by the MITRE ATT&CK project.

By approaching the search of inurl:concrete/single_pages/dashboard/reports/forms/legacy.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 9.5.3 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Content Management System

Name

• Concrete CMS

Version

• 9.5.0
• 9.5.1
• 9.5.2

License

• open-source

CPE 2.3info

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CPE 2.2info

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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