The Document Gallery WordPress plugin through 5.1.1 does not sanitise or escape several gallery shortcode attributes before embedding them in a single-quoted HTML attribute in the rendered gallery markup, allowing users with the Contributor role and above to inject arbitrary event handlers that execute when a higher privileged user views the content.

The Document Gallery WordPress plugin through 5.1.1 does not sanitise or escape several gallery shortcode attributes before embedding them in a single-quoted HTML attribute in the rendered gallery markup, allowing users with the Contributor role and above to inject arbitrary event handlers that execute when a higher privileged user views the content.