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CVE-2026-77203: Groups – Memberships and Access Control

Severity

8.8 (HIGH)

Vendor

ITTHINX

Affected versions

0 through 4.6.0

Patch status

Unknown

Published

2026-09-26T18:16:29.917

Modified

2026-09-26T23:16:35.700

Why it matters

This matters because the affected product may be exposed on public websites. A vulnerable plugin can create a direct path to site compromise, malicious code deployment, or data theft.

Recommended admin actions

• Review and patch based on exposure, asset criticality, and business impact.
• Check whether the affected WordPress plugin or theme is installed.
• Update, disable, or remove the affected component if present.

Technical summary

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.

View the official NVD record for CVE-2026-77203

CVE data is sourced from NVD/CNA records and optional enrichment. Validate against the vendor advisory before taking production action.