The underlying issue arises from the WP Photo Album Plus plugin’s handling of the 'shortcode' parameter. The code fails to properly sanitize or escape user supplied values, allowing an attacker to embed arbitrary JavaScript. When an unsuspecting user follows a manipulated link containing a malicious shortcode, the script executes in the victim’s browser. This can lead to cookie theft, session hijacking, defacement or the execution of further malware in the victim’s context. The vulnerability is a classic Reflected Cross‑Site Scripting flaw and is categorized as CWE‑80.

The flaw exists in all releases of WP Photo Album Plus up to and including 9.1.05.008 from the vendor opajaap. Site owners deploying any of these versions in a WordPress installation are potentially exposed unless the 'shortcode' feature is disabled or the plugin is updated.

The CVSS score of 7.1 signals that the flaw is moderately serious. The EPSS score is below 1 %, indicating that, at present, the likelihood of exploitation is low, and it is not listed in CISA’s KEV catalog. Exploitation requires no authentication; the attacker only needs to craft a link that includes a malicious value for the 'shortcode' parameter and convince a user to click it. Because the vulnerability operates entirely on the client side, the attack surface is broad, and any user visiting a compromised page could be impacted.