CVE-2025-2967: ConcreteCMS HTML Block XSS Vulnerability
Summary
CVE-2025-2967: ConcreteCMS Cross-Site Scripting (XSS) via HTML Block Text Field. Affects concrete5/concrete5 versions < 9.3.9. No fix is published. How to fix ↓
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Background
ConcreteCMS is an open-source content management system (CMS) designed for building and managing websites. It offers a user-friendly interface, customizable themes, and a variety of add-ons to enhance functionality. However, versions up to 9.3.9 are vulnerable to a Cross-Site Scripting (XSS) attack through the HTML Block Handler, which can allow attackers to inject malicious HTML content.
Vulnerability Detail
A vulnerability exists in ConcreteCMS versions up to 9.3.9, specifically in the Save function of the HTML Block Handler component. This vulnerability arises from improper handling of user input, allowing an attacker to manipulate the 'content' argument and perform HTML injection. The implications of this vulnerability are significant, as it can lead to unauthorized script execution in the context of a user's browser, potentially compromising user data and session integrity. The vulnerability has been publicly disclosed, and the vendor has not responded to the initial report.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a temporary workaround, you can sanitize user input in the HTML Block text field to prevent the execution of malicious scripts. Implementing input validation and escaping output can help mitigate the risk until an update is applied.
Conclusion
In summary, the vulnerability identified as CVE-2025-2967 in ConcreteCMS allows for Cross-Site Scripting attacks through the HTML Block Handler. Users are advised to update to the latest version to protect against potential exploits. Until the update is applied, implementing input sanitization can serve as a temporary measure.
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FAQ
Cross-Site Scripting (XSS) is a security vulnerability that allows attackers to inject malicious scripts into web pages viewed by other users, potentially compromising their data and session.
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If exploited, this vulnerability can lead to unauthorized access to user sessions, data theft, and the execution of malicious scripts in the context of the affected user's browser.
Yes, a patch is available in ConcreteCMS version 9.4.0 and later. It is recommended to update to this version to mitigate the vulnerability.
The CVSS score of this vulnerability is 3.5, indicating a moderate level of severity.
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