Is Simple Membership safe? Known vulnerabilities and latest version

The Simple Membership WordPress plugin before 4.8.3 does not avoid transmitting a newly registered member's plaintext password in a URL query string when an optional auto-login-after-registration feature is enabled, exposing the credential in browser history and in web server, proxy, and CDN access logs to anyone able to read them.

The Simple Membership plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'country' parameter in all versions up to, and including, 4.8.4 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Unauthenticated attackers may also exploit this vulnerability when the plugin's Enable Free Membership feature is turned on, as it permits anonymous front-end registration and profile submission.

The Simple Membership plugin for WordPress is vulnerable to unauthorized modification of data and sensitive information disclosure in versions up to, and including, 4.8.3 via the resend-activation and email-activation endpoints. The endpoints are dispatched from SwpmInitTimeTasks::check_and_do_email_activation() on frontend init with no authentication, nonce, capability, or ownership check, and the recipient address used by SwpmRegistration::send_reg_email() is taken from an attacker-controlled $_POST['email'] parameter (overriding the member's registered address). This makes it possible for unauthenticated attackers to redirect an arbitrary pending member's activation email — and the follow-up 'registration complete' email containing the member's username and plaintext password — to an attacker-chosen address, and to then activate that member's account without their consent.

Contributor Broken Access Control in Simple Membership <= 4.8.2 versions.

The Simple Membership WordPress plugin before 4.7.8 does not validate that the membership level supplied in a PayPal payment notification matches the level configured for the paid payment button, allowing members to pay for a lower-priced membership while being granted a higher, more privileged membership level.

The Simple Membership plugin for WordPress is vulnerable to Authentication Bypass leading to Administrator Account Takeover in versions up to, and including, 4.8.0. This is due to improper identity verification during the public registration flow in WordPress Multisite environments, where the plugin binds new Simple Membership records to existing global WordPress users based solely on matching username and email, without requiring password verification or ownership proof, and fails to properly detect Administrator roles on child sites. This makes it possible for unauthenticated attackers to take over Administrator accounts on child sites in a Multisite network by registering a Simple Membership account with a victim's credentials on a site where public registration is enabled, then updating the victim's global WordPress password through the profile edit functionality. The vulnerability was partially patched in version 4.8.1.

The Simple Membership WordPress plugin before 4.7.7 does not verify that a PayPal payment notification was sent to the site's own configured merchant account before activating a membership, allowing unauthenticated users to activate or extend a membership using a payment made to an arbitrary PayPal account they control.

Unauthenticated Broken Access Control in Simple Membership <= 4.7.8 versions.

The Simple Membership WordPress plugin before 4.7.8 does not verify whether user creation failed during registration before using the returned value as a user ID to update an account, allowing unauthenticated attackers to overwrite the primary administrator's account data (including the email address) and take over that account through the password reset flow.

The Simple Membership WordPress plugin before 4.7.8 does not sanitise a subscriber name value received from an unauthenticated payment approval request, nor escape it when displaying it in the administration dashboard, allowing unauthenticated attackers to store arbitrary JavaScript that executes in an administrator's session.

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

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.

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.