Auth bypass in Joedolson My-Calendar
CVE-2026-40308
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.
Vulnerability class: IDOR (Insecure Direct Object Reference)
Published · last modified .
EPSS exploit prediction
EPSS: 0.011 (65.2th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 65th percentile — 65.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.009 · newest: 0.011 · change: +0.002
Affected products
- Joedolson My-Calendar — versions < 3.7.7