This vulnerability (CVE-2026-30894) in Joomla! CMS arises from improper neutralization of input during web page generation (CWE-79), specifically in the content history component. The lack of output escaping enables cross-site scripting attacks, which can be triggered by users with high privileges and require some user interaction. The issue affects Joomla! CMS versions 3.0.0 through 5.4.5 and 6.0.0 through 6.1.0. The CVSS 4.0 vector indicates network attack vector, low attack complexity, no attack traceability, partial user interaction, and limited impact on confidentiality, integrity, and availability. No vendor advisory or patch information is currently available, and no exploits have been observed in the wild.

Successful exploitation could allow an attacker with high privileges to execute arbitrary scripts in the context of the affected Joomla! CMS instance, potentially leading to session hijacking, defacement, or other malicious actions. However, the attack requires user interaction and privileges, and the impact on confidentiality, integrity, and availability is limited as per the CVSS vector. No known active exploitation has been reported.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, administrators should consider restricting access to the content history component to trusted users only and monitor for suspicious activity. Avoid exposing the affected versions publicly if possible.