Groups <= 4.6.0 - Authenticated (Subscriber+) Privilege Escalation via 'groups_join' Shortcode

{
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "cveMetadata": {
    "cveId": "CVE-2026-77203",
    "assignerOrgId": "b15e7b5b-3da4-40ae-a43c-f7aa60e62599",
    "assignerShortName": "Wordfence",
    "dateUpdated": "2026-09-26T22:51:17.071Z",
    "dateReserved": "2026-08-20T18:03:15.864Z",
    "datePublished": "2026-09-26T17:28:59.609Z",
    "state": "PUBLISHED"
  },
  "containers": {
    "cna": {
      "providerMetadata": {
        "orgId": "b15e7b5b-3da4-40ae-a43c-f7aa60e62599",
        "shortName": "Wordfence",
        "dateUpdated": "2026-09-26T17:28:59.609Z"
      },
      "title": "Groups <= 4.6.0 - Authenticated (Subscriber+) Privilege Escalation via 'groups_join' Shortcode",
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "affected": [
        {
          "vendor": "itthinx",
          "product": "Groups – Memberships and Access Control",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0",
              "status": "affected",
              "versionType": "semver",
              "lessThanOrEqual": "4.6.0"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "lang": "en",
              "description": "CWE-269 Improper Privilege Management",
              "cweId": "CWE-269",
              "type": "CWE"
            }
          ]
        }
      ],
      "references": [
        {
          "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/e86dddc9-c1d3-426b-8ec7-2e56dc3c2379?source=cve"
        },
        {
          "url": "https://plugins.trac.wordpress.org/browser/groups/tags/4.5.0/lib/views/class-groups-shortcodes.php#L586"
        },
        {
          "url": "https://plugins.trac.wordpress.org/browser/groups/tags/4.5.0/lib/views/class-groups-shortcodes.php#L624"
        },
        {
          "url": "https://plugins.trac.wordpress.org/browser/groups/tags/4.5.0/lib/views/class-groups-shortcodes.php#L463"
        },
        {
          "url": "https://plugins.trac.wordpress.org/browser/groups/tags/4.5.0/lib/wp/class-groups-wordpress.php#L248"
        },
        {
          "url": "https://plugins.trac.wordpress.org/browser/groups/tags/4.5.0/lib/views/class-groups-shortcodes.php#L521"
        },
        {
          "url": "https://plugins.trac.wordpress.org/changeset/3693123/groups"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "version": "3.1",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "baseScore": 8.8,
            "baseSeverity": "HIGH"
          }
        }
      ],
      "timeline": [
        {
          "time": "2026-09-26T04:34:00.000Z",
          "lang": "en",
          "value": "Disclosed"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "daroo",
          "type": "finder"
        }
      ]
    },
    "adp": [
      {
        "providerMetadata": {
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP",
          "dateUpdated": "2026-09-26T22:51:17.071Z"
        },
        "title": "CISA ADP Vulnrichment",
        "metrics": [
          {}
        ]
      }
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  }
}