{"api_version":"1","generated_at":"2026-10-16T08:10:58+00:00","cve":"CVE-2026-104798","urls":{"html":"https://cve.report/CVE-2026-104798","api":"https://cve.report/api/cve/CVE-2026-104798.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-104798","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-104798"},"summary":{"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":"PUBLISHED","assigner":"Wordfence","published_at":"2026-10-16 05:17:28","updated_at":"2026-10-16 05:17:28"},"problem_types":["CWE-269","CWE-269 CWE-269 Improper Privilege 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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."}],"metrics":[{"cvssV3_1":{"baseScore":9.8,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-269","description":"CWE-269 Improper Privilege Management","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-10-16T04:27:04.876Z","orgId":"b15e7b5b-3da4-40ae-a43c-f7aa60e62599","shortName":"Wordfence"},"references":[{"url":"https://www.wordfence.com/threat-intel/vulnerabilities/id/e8aa6ee7-525e-4458-9f5b-1e729afe448c?source=cve"},{"url":"https://plugins.trac.wordpress.org/browser/my-calendar/tags/3.8.6/my-calendar-navigation.php#L248"},{"url":"https://plugins.trac.wordpress.org/browser/my-calendar/tags/3.8.6/my-calendar-navigation.php#L260"},{"url":"https://plugins.trac.wordpress.org/browser/my-calendar/tags/3.8.6/my-calendar-search.php#L221"},{"url":"https://plugins.trac.wordpress.org/browser/my-calendar/tags/3.8.6/my-calendar-search.php#L170"},{"url":"https://plugins.trac.wordpress.org/browser/my-calendar/tags/3.8.6/my-calendar-shortcodes.php#L102"},{"url":"https://plugins.trac.wordpress.org/browser/my-calendar/tags/3.8.6/my-calendar-output.php#L1622"},{"url":"https://plugins.trac.wordpress.org/changeset?reponame=&old=3746389%40my-calendar&new=3746389%40my-calendar"}],"timeline":[{"lang":"en","time":"2026-10-02T13:27:02.000Z","value":"Vendor Notified"},{"lang":"en","time":"2026-10-15T16:25:37.000Z","value":"Disclosed"}],"title":"My Calendar <= 3.8.7 - Unauthenticated Privilege Escalation to 'mcs' Parameter via Reflected Shortcode Injection into 'above' Attribute"}},"cveMetadata":{"assignerOrgId":"b15e7b5b-3da4-40ae-a43c-f7aa60e62599","assignerShortName":"Wordfence","cveId":"CVE-2026-104798","datePublished":"2026-10-16T04:27:04.876Z","dateReserved":"2026-10-02T13:12:10.980Z","dateUpdated":"2026-10-16T04:27:04.876Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-16 05:17:28","lastModifiedDate":"2026-10-16 05:17:28","problem_types":["CWE-269","CWE-269 CWE-269 Improper Privilege Management"],"metrics":{"cvssMetricV31":[{"source":"security@wordfence.com","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"104798","Ordinal":"1","Title":"My Calendar <= 3.8.7 - Unauthenticated Privilege Escalation to '","CVE":"CVE-2026-104798","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"104798","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"My Calendar <= 3.8.7 - Unauthenticated Privilege Escalation to '"}]}}}