Concrete CMS up to 9.5.0 URL legacy cross site scripting

Summaryinfo

A vulnerability has been found in Concrete CMS up to 9.5.0 and classified as critical. This affects an unknown function of the file /dashboard/reports/forms/legacy of the component URL Handler. Performing a manipulation results in cross site scripting. This vulnerability is cataloged as CVE-2026-8245. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in Concrete CMS up to 9.5.0. It has been classified as critical. This affects an unknown part of the file /dashboard/reports/forms/legacy of the component URL Handler. The manipulation with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as CWE-83. The product does not neutralize or incorrectly neutralizes "javascript:" or other URIs from dangerous attributes within tags, such as onmouseover, onload, onerror, or style. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Concrete CMS 9.5.0 and below is vulnerable to Reflected XSS in Legacy Pagination via HTML attribute injection. Concrete\Core\Legacy\Pagination builds pagination links by raw-interpolating its $URL field into href="" (<a href="{$linkURL}" …>). Any authenticated admin or report viewer with access to `/dashboard/reports/forms/legacy` who clicks the crafted URL fires the payload in their session. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 6.0 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori (Tenzai) for reporting

The weakness was shared by Yonatan Drori. The advisory is shared at documentation.concretecms.org. This vulnerability is uniquely identified as CVE-2026-8245 since 05/09/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 05/24/2026). MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• Content Management System

Vendor

• Concrete

Name

• CMS

Version

• 9.0
• 9.1
• 9.2
• 9.3
• 9.4
• 9.5.0

License

• open-source

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CPE 2.2info

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