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CVE-2026-104798

CRITICAL 9.8 CVSS 3.1
Published
October 16, 2026
Last modified
October 16, 2026
NVD status
Deferred
Reported by
security@wordfence.com
Weakness
CWE-269
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

Affected WordPress components

  • My Calendar – Accessible Event Manager Plugin · my-calendar
    Confirmed match Active
    Up to and including 3.4.24; From 3.5 (including) to 3.5.21 (including); From 3.8 (including) to 3.8.7 (including); From 3.7 (including) to 3.7.17 (including); From 3.6 (including) to 3.6.17 (including)
    View on WordPress.org

A confirmed match is backed by the plugin or theme slug. A possible match is based on the product name only and should be verified.

Affected products and versions

  • joedolson My Calendar – Accessible Event Manager — Up to and including 3.4.24
  • joedolson My Calendar – Accessible Event Manager — From 3.5 (including) to 3.5.21 (including)
  • joedolson My Calendar – Accessible Event Manager — From 3.6 (including) to 3.6.17 (including)
  • joedolson My Calendar – Accessible Event Manager — From 3.7 (including) to 3.7.17 (including)
  • joedolson My Calendar – Accessible Event Manager — From 3.8 (including) to 3.8.7 (including)

References