The Brevo - Email, SMS, Web Push, Chat, and more. plugin for WordPress is vulnerable to authorization bypass due to type juggling in all versions up to, and including, 3.3.0. This is due to the use of loose comparison (==) instead of strict comparison (===) when validating the installation ID in the /wp-json/mailin/v1/mailin_disconnect REST API endpoint. This makes it possible for unauthenticated attackers to disconnect the Brevo integration, delete the API key, remove all subscription forms, and reset plugin settings by sending a boolean true value for the id parameter, which bypasses the authorization check through PHP type juggling.
Weakness
The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.
Extended Description
When the product accesses the resource using an incompatible type, this could trigger logical errors because the resource does not have expected properties. In languages without memory safety, such as C and C++, type confusion can lead to out-of-bounds memory access. While this weakness is frequently associated with unions when parsing data with many different embedded object types in C, it can be present in any application that can interpret the same variable or memory location in multiple ways. This weakness is not unique to C and C++. For example, errors in PHP applications can be triggered by providing array parameters when scalars are expected, or vice versa. Languages such as Perl, which perform automatic conversion of a variable of one type when it is accessed as if it were another type, can also contain these issues.
References
- https://plugins.trac.wordpress.org/browser/mailin/tags/3.2.9/sendinblue.php#L1795
- https://plugins.trac.wordpress.org/browser/mailin/tags/3.2.9/sendinblue.php#L1833
- https://plugins.trac.wordpress.org/changeset/3448639/
- https://www.wordfence.com/threat-intel/vulnerabilities/id/f29e5b19-2505-4b02-92c7-071833de6bc2?source=cve