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.
Analysis
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Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| joedolson | My Calendar – Accessible Event Manager | unaffected |
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Remediation
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Tracking
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Advisories
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References
History
Fri, 16 Oct 2026 04:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | My Calendar <= 3.8.7 - Unauthenticated Privilege Escalation to 'mcs' Parameter via Reflected Shortcode Injection into 'above' Attribute | |
| Weaknesses | CWE-269 | |
| References |
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| Metrics |
cvssV3_1
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Subscriptions
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MITRE
Status: PUBLISHED
Assigner: Wordfence
Published:
Updated: 2026-10-16T04:27:04.876Z
Reserved: 2026-10-02T13:12:10.980Z
Link: CVE-2026-104798
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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Weaknesses
-
CWE-269
Improper Privilege Management