Concrete CMS up to 8.5.20/9.4.2 on Concrete Conversation Messages Dashboard cross site scripting

Summaryinfo

A vulnerability was found in Concrete CMS up to 8.5.20/9.4.2 on Concrete. It has been classified as problematic. This affects an unknown part of the component Conversation Messages Dashboard. This manipulation causes cross site scripting. This vulnerability is registered as CVE-2025-8571. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as problematic was found in Concrete CMS up to 8.5.20/9.4.2 on Concrete. Affected by this vulnerability is an unknown code block of the component Conversation Messages Dashboard. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is 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. As an impact it is known to affect integrity. The summary by CVE is:

Concrete CMS 9 to 9.4.2 and versions below 8.5.21 are vulnerable to Reflected Cross-Site Scripting (XSS) in the Conversation Messages Dashboard Page. Unsanitized input could cause theft of session cookies or tokens, defacement of web content, redirection to malicious sites, and (if victim is an admin), the execution of unauthorized actions. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 4.8 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Fortbridge https://fortbridge.co.uk/  for performing a penetration test and vulnerability assessment on Concrete CMS and reporting this issue.

The advisory is shared at documentation.concretecms.org. This vulnerability is known as CVE-2025-8571 since 08/04/2025. The exploitation appears to be easy. The attack can be launched remotely. The exploitation requires an enhanced level of successful authentication. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

Upgrading to version 8.5.21 or 9.4.3 eliminates this vulnerability.

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Productinfo

Type

• Content Management System

Vendor

• Concrete

Name

• CMS

Version

• 8.5.0
• 8.5.1
• 8.5.2
• 8.5.3
• 8.5.4
• 8.5.5
• 8.5.6
• 8.5.7
• 8.5.8
• 8.5.9
• 8.5.10
• 8.5.11
• 8.5.12
• 8.5.13
• 8.5.14
• 8.5.15
• 8.5.16
• 8.5.17
• 8.5.18
• 8.5.19
• 8.5.20
• 9.4.0
• 9.4.1
• 9.4.2

License

• open-source

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• 🔒
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CPE 2.2info

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