CVE-2026-27543

The Mstore Api plugin for WordPress is vulnerable to Authentication Bypass via JWT Forgery in versions up to, and including, 4.20.0. This is due to missing cryptographic signature verification in the FirebasePhoneAuthHelper::verify_id_token() function, which decodes and validates Firebase ID token claims (alg, kid, aud, iss) but never calls openssl_verify() or any equivalent to validate the JWT signature against Google's actual public key certificates. This makes it possible for unauthenticated attackers to forge a Firebase Phone Auth JWT signed with a self-generated RSA key pair and impersonate any phone number, resulting in unauthorized access to existing WordPress accounts or creation of new arbitrary accounts.

The MStore API WordPress plugin before 4.21.0 does not verify the payment with the payment gateway before marking an order as paid on several of its payment-completion endpoints, allowing an unauthenticated attacker to mark an arbitrary order fully paid without paying and obtain goods or services for free.

The MStore API WordPress plugin before 4.21.1 does not verify that the order targeted by its wallet payment handling belongs to the requester, and does not deduct the wallet balance for most payment methods. This allows any authenticated user, including Subscribers, to mark arbitrary orders as paid without any payment being taken.

The MStore API WordPress plugin before version 4.21.1 does not verify that the order targeted by one of its delivery endpoints belongs to the requester. This allows any authenticated user, including Subscribers, to mark arbitrary orders as completed and paid without any payment being made.

The MStore API WordPress plugin before 4.21.0 does not perform authorization or purchase-ownership checks on its REST product-review creation route, allowing an unauthenticated attacker to create WooCommerce product reviews with an attacker-chosen reviewer name, email and star rating on stores configured to accept reviews only from verified owners.

The MStore API WordPress plugin before 4.21.0 does not restrict its vendor-orders endpoint to the caller's own orders, allowing any authenticated user, including Subscribers, to read every WooCommerce order in the store together with each customer's personal information.

The MStore API WordPress plugin before 4.21.0 does not correctly verify the cryptographic signature of the token used to authenticate its phone-based login, allowing unauthenticated attackers who know a registered user's phone number to forge a token and take over that user's account, including administrator accounts.

The MStore API plugin for WordPress contains a missing authorization vulnerability that allows exploiting incorrectly configured access control security levels. This issue affects versions up to and including 4.18.4.

The MStore API plugin for WordPress up to version 4.18.3 has an IDOR vulnerability in the update_user_profile() function. An authenticated user with Subscriber access can modify arbitrary meta fields on their account, including sensitive ones like wp_user_level, without proper validation.