{"id":"CVE-2026-104798","revision":"dbbfd7f6116743d8a2393a7677c37e2e","records":[{"revision":"dbbfd7f6116743d8a2393a7677c37e2e","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-104798","aliases":[],"title":"My Calendar <= 3.8.7 - Unauthenticated Privilege Escalation to 'mcs' Parameter via Reflected Shortcode Injection into 'above' Attribute","description":"The My Calendar – Accessible Event Manager plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 3.8.7. The public `mcs` GET parameter is reflected into post content unsanitized before WordPress core's `do_shortcode` filter runs, allowing an unauthenticated attacker to inject a nested `[my_calendar above=...]` shortcode; `mc_generate_calendar_nav()` then splits the `above` attribute on commas and dispatches each element via `call_user_func()` with no authentication, authorization, or callable allowlist check. This makes it possible for unauthenticated attackers to invoke arbitrary loaded PHP functions, enabling a call chain in which the shortcode `$params` array is passed to `edit_user()` — which PHP coerces to integer `1` as the `$user_id` argument — overwriting the credentials of the initial Administrator account (user ID 1) and granting the attacker full wp-admin access. Exploitation is trivially reachable via the plugin's auto-generated `/my-calendar/` page, which is publicly accessible by default upon plugin activation.","state":0,"publishedAt":"2026-10-16T04:27:04.876+00:00","modifiedAt":"2026-10-16T17:07:17.621+00:00","affected":[{"ecosystem":"Vendor product","name":"My Calendar – Accessible Event Manager","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"joedolson\",\n                    \"product\": \"My Calendar – Accessible Event Manager\",\n                    \"versions\": [\n                        {\n                            \"version\": \"0\",\n                            \"status\": \"affected\",\n                            \"lessThanOrEqual\": \"3.4.24\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"3.5\",\n                            \"status\": \"affected\",\n                            \"lessThanOrEqual\": \"3.5.21\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"3.6\",\n                            \"status\": \"affected\",\n                            \"lessThanOrEqual\": \"3.6.17\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"3.7\",\n                            \"status\": \"affected\",\n                            \"lessThanOrEqual\": \"3.7.17\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"3.8\",\n                            \"status\": \"affected\",\n                            \"lessThanOrEqual\": \"3.8.7\",\n                            \"versionType\": \"semver\"\n                        }\n                    ],\n                    \"defaultStatus\": \"unaffected\"\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://www.wordfence.com/threat-intel/vulnerabilities/id/e8aa6ee7-525e-4458-9f5b-1e729afe448c?source=cve","https://plugins.trac.wordpress.org/browser/my-calendar/tags/3.8.6/my-calendar-navigation.php#L248","https://plugins.trac.wordpress.org/browser/my-calendar/tags/3.8.6/my-calendar-navigation.php#L260","https://plugins.trac.wordpress.org/browser/my-calendar/tags/3.8.6/my-calendar-search.php#L221","https://plugins.trac.wordpress.org/browser/my-calendar/tags/3.8.6/my-calendar-search.php#L170","https://plugins.trac.wordpress.org/browser/my-calendar/tags/3.8.6/my-calendar-shortcodes.php#L102","https://plugins.trac.wordpress.org/browser/my-calendar/tags/3.8.6/my-calendar-output.php#L1622","https://plugins.trac.wordpress.org/changeset?reponame=&old=3746389%40my-calendar&new=3746389%40my-calendar"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-104798","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-104798","identifiers":["CVE-2026-104798"]},"retained":false,"historicalAffected":[]}],"coverage":[]}