CVE-2026-77027 is a stored XSS vulnerability in the Fabrik extension for Joomla, specifically affecting versions from 1.0.0 up to and including 4.7.1. The flaw is due to improper neutralization of input during web page generation in the jsactions feature, enabling unauthenticated attackers to inject and store malicious scripts that execute in the context of users visiting the affected site. The vulnerability has a CVSS 4.0 base score of 8.6, indicating high severity with network attack vector, no privileges required, and high impact on confidentiality and integrity.

Successful exploitation allows an unauthenticated attacker to execute arbitrary scripts in the context of users visiting the affected Joomla site running the vulnerable Fabrik extension. This can lead to session hijacking, defacement, or other malicious actions impacting confidentiality and integrity of user data. There are no known exploits in the wild at this time.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch link is provided in the available data. Users should monitor the Fabrik extension vendor advisories for updates and apply any official patches once available. Until then, consider disabling or restricting the jsactions feature if feasible.