Is Groups safe? Known vulnerabilities and latest version

The Groups – Memberships and Access Control plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 4.6.0. This is due to the groups_join() function deriving group-join eligibility from the ambient post's author capabilities via the global $post->post_author rather than from the currently authenticated user's own capabilities, while simultaneously minting and returning a valid groups-join-data hash and WordPress nonce for the caller in the same response — eliminating all authorization barriers to self-enrollment. This makes it possible for authenticated attackers, with Subscriber-level access and above, to enroll themselves into any group including privileged groups carrying the groups_admin_groups capability, and to subsequently create and join a group containing every registered WordPress capability, effectively escalating their privileges to Administrator. Exploitation requires the attacker to supply an Administrator-authored post ID via the post_ID parameter of the authenticated wp_ajax_parse_media_shortcode handler in order to establish the privileged ambient post context used by the flawed authorization check.

The Groups plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'groups_group_info' shortcode in all versions up to, and including, 3.10.0 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 Groups plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 3.7.0 via the 'group_id' parameter of the group_join function due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with Subscriber-level access and above, to register for groups other than ones set in the shortcode.