Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in WPDeveloper Essential Blocks for Gutenberg allows Stored XSS.This issue affects Essential Blocks for Gutenberg: from n/a through 4.5.3.

The Essential Blocks – Page Builder Gutenberg Blocks, Patterns & Templates plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's widgets in all versions up to, and including, 4.5.2 due to insufficient input sanitization and output escaping on user supplied attributes such as listStyle. This makes it possible for authenticated attackers with contributor-level and above permissions to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The Essential Blocks – Page Builder Gutenberg Blocks, Patterns & Templates plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the blockId parameter in all versions up to, and including, 4.5.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor access or higher, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The Essential Blocks WordPress plugin before 4.4.3 does not prevent unauthenticated attackers from overwriting local variables when rendering templates over the REST API, which may lead to Local File Inclusion attacks.

The Essential Blocks – Page Builder Gutenberg Blocks, Patterns & Templates plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the Table of Contents block in all versions up to, and including, 4.4.6 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 Essential Blocks plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 4.2.0 via deserialization of untrusted input in the get_posts function. This allows unauthenticated attackers to inject a PHP Object. No POP chain is present in the vulnerable plugin. 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 Essential Blocks plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 4.2.0 via deserialization of untrusted input in the get_products function. This allows unauthenticated attackers to inject a PHP Object. No POP chain is present in the vulnerable plugin. 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 Essential Blocks plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 4.0.6. This is due to missing or incorrect nonce validation on the save function. This makes it possible for unauthenticated attackers to change plugin settings via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

The Essential Blocks plugin for WordPress is vulnerable to unauthorized use of functionality due to a missing capability check on the template_count function in versions up to, and including, 4.0.6. This makes it possible for subscriber-level attackers to obtain plugin template information. While a nonce check is present, it is only executed when a nonce is provided. Not providing a nonce results in the nonce verification to be skipped. There is no capability check.

The Essential Blocks plugin for WordPress is vulnerable to unauthorized use of functionality due to a missing capability check on the templates function in versions up to, and including, 4.0.6. This makes it possible for subscriber-level attackers to obtain plugin template information. While a nonce check is present, it is only executed when a nonce is provided. Not providing a nonce results in the nonce verification to be skipped. There is no capability check.