# CVE-2026-40308

> Vulnerability.

## Description

My Calendar is a WordPress plugin for managing calendar events. In versions 3.7.6 and below, the mc_ajax_mcjs_action AJAX endpoint, registered for unauthenticated users, passes user-supplied arguments through parse_str() without validation, allowing injection of arbitrary parameters including a site value. On WordPress Multisite installations, this enables an unauthenticated attacker to call switch_to_blog() with an arbitrary site ID and extract calendar events from any sub-site on the network, including private or hidden events. On standard Single Site installations, switch_to_blog() does not exist, causing an uncaught PHP fatal error and crashing the worker thread, creating an unauthenticated denial of service vector. This issue has been fixed in version 3.7.7.

## Key facts

- **CVE ID:** CVE-2026-40308
- **Published:** 2026-04-16
- **CWE codes:** CWE-639

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40308

## Citation

> AI Analytics. CVE-2026-40308. Retrieved 2026-07-19 from https://api.ai-analytics.org/cve/CVE-2026-40308. Derived from NIST NVD. Licensed CC0.

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