The ci4ms CMS prior to version 0.31.0.0 contains a stored cross-site scripting vulnerability (CWE-79) due to improper neutralization of user input during web page generation. Specifically, the blog category title field does not sanitize input correctly, enabling attackers with at least low privileges to inject malicious JavaScript code. This code is stored on the server and later rendered in multiple contexts including public-facing blog category pages, administrative interfaces, and blog post views without proper output encoding, resulting in a critical security flaw. The vulnerability has a CVSS 3.1 base score of 10.0, indicating critical severity with network attack vector, low attack complexity, no user interaction required, and impacts on confidentiality, integrity, and availability. The issue is fixed in ci4ms version 0.31.0.0.

Successful exploitation allows an attacker to execute arbitrary JavaScript in the context of affected users, potentially leading to theft of sensitive information, session hijacking, unauthorized actions, and full compromise of the application and its data. The vulnerability affects all users who view the compromised blog category pages, including administrators and public users. The CVSS score of 10.0 reflects the critical nature and broad impact of this stored XSS vulnerability.

Upgrade ci4ms to version 0.31.0.0 or later, where this vulnerability has been patched. No other mitigations are indicated or required as the fix addresses the root cause by properly sanitizing and encoding user input in the blog category title field.