joedolson My Calendar Plugin up to 3.8.7 on WordPress Shortcode mc_generate_calendar_nav mcs privileges management

Summaryinfo

A vulnerability marked as critical has been reported in joedolson My Calendar Plugin up to 3.4.24/3.5.21/3.6.17/3.7.17/3.8.7. This impacts the function mc_generate_calendar_nav of the component Shortcode Handler. Performing a manipulation of the argument mcs results in privileges management. This vulnerability is cataloged as CVE-2026-104798. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in joedolson My Calendar Plugin up to 3.4.24/3.5.21/3.6.17/3.7.17/3.8.7. It has been classified as critical. This affects the function mc_generate_calendar_nav of the component Shortcode Handler. The manipulation of the argument mcs with an unknown input leads to a privileges management vulnerability. CWE is classifying the issue as 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. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at wordfence.com. This vulnerability is uniquely identified as CVE-2026-104798 since 10/02/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/16/2026). MITRE ATT&CK project uses the attack technique T1068 for this issue.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• WordPress Plugin

Vendor

• joedolson

Name

• My Calendar Plugin

Version

• 3.4.0
• 3.4.1
• 3.4.2
• 3.4.3
• 3.4.4
• 3.4.5
• 3.4.6
• 3.4.7
• 3.4.8
• 3.4.9
• 3.4.10
• 3.4.11
• 3.4.12
• 3.4.13
• 3.4.14
• 3.4.15
• 3.4.16
• 3.4.17
• 3.4.18
• 3.4.19
• 3.4.20
• 3.4.21
• 3.4.22
• 3.4.23
• 3.4.24
• 3.5.0
• 3.5.1
• 3.5.2
• 3.5.3
• 3.5.4
• 3.5.5
• 3.5.6
• 3.5.7
• 3.5.8
• 3.5.9
• 3.5.10
• 3.5.11
• 3.5.12
• 3.5.13
• 3.5.14
• 3.5.15
• 3.5.16
• 3.5.17
• 3.5.18
• 3.5.19
• 3.5.20
• 3.5.21
• 3.6.0
• 3.6.1
• 3.6.2
• 3.6.3
• 3.6.4
• 3.6.5
• 3.6.6
• 3.6.7
• 3.6.8
• 3.6.9
• 3.6.10
• 3.6.11
• 3.6.12
• 3.6.13
• 3.6.14
• 3.6.15
• 3.6.16
• 3.6.17
• 3.7.0
• 3.7.1
• 3.7.2
• 3.7.3
• 3.7.4
• 3.7.5
• 3.7.6
• 3.7.7
• 3.7.8
• 3.7.9
• 3.7.10
• 3.7.11
• 3.7.12
• 3.7.13
• 3.7.14
• 3.7.15
• 3.7.16
• 3.7.17
• 3.8.0
• 3.8.1
• 3.8.2
• 3.8.3
• 3.8.4
• 3.8.5
• 3.8.6
• 3.8.7

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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