CVE-2026-104798 (GCVE-0-2026-104798)

Vulnerability from cvelistv5 – Published: 2026-10-16 04:27 – Updated: 2026-10-16 17:07
VLAI
Title
My Calendar <= 3.8.7 - Unauthenticated Privilege Escalation to 'mcs' Parameter via Reflected Shortcode Injection into 'above' Attribute
Summary
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.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-16 16:48 UTC
CWE
  • CWE-269 - Improper Privilege Management
Assigner
Wordfence CNA under the mitre root
CNA scorecard C 65/100 over 2289 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
joedolson My Calendar – Accessible Event Manager Affected: 0 , ≤ 3.4.24 (semver)
Affected: 3.5 , ≤ 3.5.21 (semver)
Affected: 3.6 , ≤ 3.6.17 (semver)
Affected: 3.7 , ≤ 3.7.17 (semver)
Affected: 3.8 , ≤ 3.8.7 (semver)
guessed Create a notification for this product.
Credits
daroo
Show details on NVD website
To clipboard 

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