The Simple Membership WordPress plugin before 4.7.5 does not verify the authenticity of Stripe webhook requests when no signing secret is configured, nor escape a value taken from them before outputting it in an administrator notice, allowing unauthenticated attackers to inject arbitrary web scripts that execute in the context of a logged-in administrator.

The Simple Membership plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 4.7.5. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for unauthenticated attackers to deactivate arbitrary member accounts by forging a charge.refunded webhook event containing a victim's subscription ID, setting the target member's account_state to 'inactive' and triggering cancellation hooks, transaction-record status changes, and cancellation notification emails. This vulnerability is exploitable only on installations where no Stripe webhook signing secret has been configured, which is the default out-of-the-box state; sites that have configured the stripe-webhook-signing-secret option are routed to the properly verified HMAC path and are not affected.

Unauthenticated Cross Site Scripting (XSS) in Simple Membership <= 4.7.2 versions.

Unauthenticated Broken Access Control in Simple Membership <= 4.7.1 versions.

The Simple Membership plugin for WordPress is vulnerable to Improper Handling of Missing Values in all versions up to, and including, 4.7.0 via the Stripe webhook handler. This is due to the plugin only validating webhook signatures when the stripe-webhook-signing-secret setting is configured, which is empty by default. This makes it possible for unauthenticated attackers to forge Stripe webhook events to manipulate membership subscriptions, including reactivating expired memberships without payment or canceling legitimate subscriptions, potentially leading to unauthorized access and service disruption.

Missing Authorization vulnerability in wp.insider Simple Membership simple-membership allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects Simple Membership: from n/a through <= 4.6.9.

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in wp.insider Simple Membership simple-membership allows Stored XSS.This issue affects Simple Membership: from n/a through <= 4.6.3.

The Simple Membership plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 4.5.5 via the WordPress core search feature. This makes it possible for unauthenticated attackers to extract sensitive data from posts that have been restricted to higher-level roles such as administrator.

URL Redirection to Untrusted Site ('Open Redirect') vulnerability in wp.insider Simple Membership simple-membership allows Phishing.This issue affects Simple Membership: from n/a through <= 4.5.3.

Improper Privilege Management vulnerability in smp7, wp.Insider Simple Membership allows Privilege Escalation.This issue affects Simple Membership: from n/a through 4.3.4.

Improper Authentication vulnerability in smp7, wp.Insider Simple Membership.This issue affects Simple Membership: from n/a through 4.3.4.

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, 4.4.5 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.

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.

The Simple Membership plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'Display Name' parameter in all versions up to, and including, 4.4.2 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This vulnerability requires social engineering to successfully exploit, and the impact would be very limited due to the attacker requiring a user to login as the user with the injected payload for execution.

URL Redirection to Untrusted Site ('Open Redirect') vulnerability in smp7, wp.Insider Simple Membership.This issue affects Simple Membership: from n/a through 4.4.1.

The Simple Membership plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the ‘environment_mode’ parameter in all versions up to, and including, 4.3.8 due to insufficient input sanitization and output escaping. 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.

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in smp7, wp.Insider Simple Membership allows Reflected XSS.This issue affects Simple Membership: from n/a through 4.3.8.

The Simple Membership plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the `list_type` parameter in versions up to, and including, 4.3.5 due to insufficient input sanitization and output escaping. Using this vulnerability, unauthenticated attackers could inject arbitrary web scripts into pages that are being executed if they can successfully trick a user into taking an action, such as clicking a malicious link.

The Simple Membership WordPress plugin before 4.2.2 does not validate and escape some of its shortcode attributes before outputting them back in the page, which could allow users with a role as low as contributor to perform Stored Cross-Site Scripting attacks which could be used against high privilege users such as admin.

The Simple Membership WordPress plugin before 4.1.3 allows user to change their membership at the registration stage due to insufficient checking of a user supplied parameter.

The Simple Membership WordPress plugin before 4.1.3 does not properly validate the membership_level parameter when editing a profile, allowing members to escalate to a higher membership level by using a crafted POST request.

The Simple Membership WordPress plugin before 4.1.1 does not properly sanitise and escape parameters before outputting them back in AJAX actions, leading to Reflected Cross-Site Scripting

The Simple Membership WordPress plugin before 4.1.0 does not have CSRF check in place when deleting Transactions, which could allow attackers to make a logged in admin delete arbitrary transactions via a CSRF attack

The Simple Membership WordPress plugin before 4.0.9 does not have CSRF check when deleting members in bulk, which could allow attackers to make a logged in admin delete them via a CSRF attack