The s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'dateformat' parameter in all versions up to, and including, <= 261011 due to insufficient input sanitization and output escaping. 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. The payload bypasses wpksespost() on save because it contains no literal angle brackets — only backslash-escaped sequences that PHP's date() materializes into HTML tag characters at render time after WordPress's shortcodeparseatts() applies stripcslashes() to the attribute value.

The s2Member Pro plugin for WordPress is vulnerable to Local File Inclusion in all versions up to, and including, 250214 via the 'template' attribute. This makes it possible for authenticated attackers, with contributor-level and above permissions, to include and execute arbitrary files on the server, allowing the execution of any PHP code in those files. This can be used to bypass access controls, obtain sensitive data, or achieve code execution.

The s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions plugin for WordPress is vulnerable to Reflected Cross-Site Scripting due to the use of addqueryarg without appropriate escaping on the URL in all versions up to, and including, 241114. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.

The s2Member Pro plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 241216 via deserialization of untrusted input from the 's2memberproremoteop' vulnerable parameter. This makes it possible for unauthenticated attackers to inject a PHP Object. No known POP chain is present in the vulnerable software. If a POP chain is present via an additional plugin or theme installed on the target system, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code.

The s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 241114 via the 'scgetdetails' function. This makes it possible for authenticated attackers, with Contributor-level access and above, to extract sensitive data including user data and database configuration information, which can lead to reading, updating, or dropping database tables. The vulnerability was partially patched in version 241114.

Cross-site scripting (XSS) vulnerability in the s2Member Pro plugin before 111220 for WordPress allows remote attackers to inject arbitrary web script or HTML via the s2memberproauthnetcheckout[coupon] parameter (aka Coupon Code field).