Simple Membership <= 4.4.3 - Authenticated(Contributor+) Stored Cross-Site Scripting via Shortcode

Vulnerability Description

The Simple Membership plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'swpm_paypal_subscription_cancel_link' shortcode in all versions up to, and including, 4.4.3 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

References

• https://www.wordfence.com/threat-intel/vulnerabilities/id/63779ab7-ba8b-459d-beb3-a32faf8f4394?source=cve
• https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3076221%40simple-membership&new=3076221%40simple-membership&sfp_email=&sfph_mail=#file31