Cybersecurity professionals consider CVE-2026-77203 an immediate threat requiring urgent mitigation.
Status: Received on 26 Sep 2026, 18:16 UTC
Published on: 26 Sep 2026, 18:16 UTC
CVSS Release: version 3
security@wordfence.com
Primary
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVE-2026-77203: 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 exploitability of CVE-2026-77203 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
CVE-2026-77203 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2026-77203, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2026-77203, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
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