CyberRota Analysis
AI-GeneratedConcrete CMS versions prior to 9.5.3 and 8.5.21 are vulnerable to stored cross-site scripting (XSS) due to inadequate validation of external link URLs in specific content blocks. This flaw allows users with page-editing permissions to inject malicious JavaScript, potentially leading to session hijacking and full administrative takeover for any user accessing the compromised page. Organizations using affected versions should prioritize patching to mitigate the risk of exploitation.
Original NVD Description
Concrete CMS 9 before 9.5.3 was vulnerable to stored cross-site scripting (XSS) in the Feature, Feature Link, Hero Image, and Image blocks and before Concrete 8.5.21 in the feature and Image blocks because the external link URL was insufficiently validated by the link filter and was rendered without output escaping. A user with page-editing permissions (such as Add Block combined with Edit Contents on a single page) could store a crafted external link value that broke out of the link markup and injected arbitrary JavaScript. The script executed in the browser session of any user who subsequently viewed, previewed, or edited the affected page, which could lead to session hijacking and escalation of privileges up to full administrative takeover. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 8.5 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks to KhanMarshai for reporting this issue.