The Astra WordPress theme versions up to 4.12.3 contain a stored XSS vulnerability due to improper neutralization of input in the `ast-page-background-meta` and `ast-content-background-meta` post meta fields. The issue stems from inadequate sanitization during meta registration and missing escaping in the `astra_get_responsive_background_obj()` function, specifically affecting CSS sub-properties like `background-color`, `background-image`, `overlay-color`, and `overlay-gradient`. This allows authenticated users with Contributor-level permissions or higher to inject arbitrary JavaScript that executes in the context of users viewing the compromised pages.

An attacker with Contributor-level access or above can exploit this vulnerability to inject persistent malicious scripts into pages, potentially leading to unauthorized actions, data theft, or session hijacking for users who view the infected pages. The vulnerability does not affect availability but impacts confidentiality and integrity to a limited extent. There are no known exploits in the wild as of the published date.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict Contributor-level access to trusted users only and consider disabling or limiting use of the affected meta fields if possible. Monitor vendor channels for updates and apply patches promptly once released.