The Portfolio Filter Gallery WordPress plugin suffers from a stored cross-site scripting vulnerability (CWE-79) due to improper neutralization of input during web page generation. Specifically, the plugin fails to adequately sanitize and escape user-supplied attributes in its 'PFG' shortcode, allowing authenticated users with contributor or higher privileges to inject arbitrary JavaScript code. This malicious code is stored and executed in the context of any user who accesses the injected page, potentially leading to session hijacking or other script-based attacks. The vulnerability affects all plugin versions up to and including 1.6.4. The CVSS 3.1 base score is 6.4, reflecting network attack vector, low attack complexity, required privileges at the contributor level, no user interaction, and partial impact on confidentiality and integrity but no impact on availability.

An attacker with contributor-level access or higher can inject persistent malicious scripts into pages via the vulnerable shortcode. These scripts execute in the browsers of users who visit the compromised pages, potentially allowing theft of sensitive information, session tokens, or performing actions on behalf of the victim user. The vulnerability does not impact system availability but affects confidentiality and integrity to a limited extent. 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. Until an official fix is released, restrict contributor-level access to trusted users only and consider disabling or removing the Portfolio Filter Gallery plugin if possible. Monitor for plugin updates from the vendor that address this vulnerability.