CVE-2026-104798
Received
Received - Intake
Privilege Escalation in My Calendar WordPress Plugin
Vulnerability report for CVE-2026-104798, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-10-16
Last updated on: 2026-10-16
Assigner: Wordfence
Description
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.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| joedolson | My | Calendar – Accessible Event Manager 0 |
| joedolson | My | Calendar – Accessible Event Manager 3.5 |
| joedolson | My | Calendar – Accessible Event Manager 3.6 |
| joedolson | My | Calendar – Accessible Event Manager 3.7 |
| joedolson | My | Calendar – Accessible Event Manager 3.8 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-269 | The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. |
