The Zoo extension for Joomla allows an attacker to craft a request that injects a malicious referer value, which is forwarded directly to the application’s redirect method without validation. This flaw permits the attacker to redirect authenticated or unauthenticated users to arbitrary external sites. While it does not provide direct code execution or data exfiltration, the redirected users may be exposed to phishing or malware sites, thereby compromising user trust and potentially leading to credential theft.

The vulnerability affects the Zoo extension from yootheme.com for Joomla in all releases earlier than version 4.1.64. Any site that installs or uses those older versions is potentially impacted.

The CVSS score of 5.1 indicates a moderate risk level. The EPSS score of 0.00295 indicates a very low likelihood of exploitation, and the issue is not listed in the CISA KEV catalog, suggesting limited known exploitation. The likely attack vector is web-based, with attackers sending crafted URLs or form submissions that include a manipulated referer header to trigger the redirect.