The Shiny Buttons WordPress plugin through 1.1.0 does not have any authorisation and CSRF in place when saving a template (wpbtn_save_template function hooked to the init action), nor sanitise and escape them before outputting them in the admin dashboard, which allow unauthenticated users to add a malicious template and lead to Stored Cross-Site Scripting issues.

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-24792
• https://wpscan.com/vulnerability/29514d8e-9d1c-4fb6-b378-f6b7374989ca