The Simply Excerpts WordPress plugin through 1.4 does not sanitize and escape some fields in the plugin settings, which could allow high-privilege users such as an administrator to inject arbitrary web scripts even when the unfiltered_html capability is disallowed (for example in a multisite setup).
https://wpscan.com/vulnerability/79b79e9c-ea4f-4188-a1b5-61dda0b5d434