My Calendar: Unauthenticated Information Disclosure (IDOR) via Multisite switch_to_blog_CVE-2026-40308

{
    "lastseen": "",
    "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 unauthenticated 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.",
    "published": "2026-04-16T21:30:52.401Z",
    "modified": "2026-04-16T21:30:52.401Z",
    "type": "cve",
    "title": "My Calendar: Unauthenticated Information Disclosure (IDOR) via Multisite switch_to_blog",
    "source": "GitHub_M",
    "references": "https://github.com/joedolson/my-calendar/security/advisories/GHSA-2mvx-f5qm-v2ch\nhttps://github.com/joedolson/my-calendar/releases/tag/v3.7.7",
    "id": "CVE-2026-40308",
    "bulletinFamily": "",
    "cwe": [
        "CWE-639"
    ],
    "cvelist": null,
    "sourceData": "joedolson my-calendar < 3.7.7",
    "sourceHref": "",
    "cvss": {
        "score": 8.8,
        "severity": "HIGH",
        "vector": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "my-calendar",
    "version": "< 3.7.7",
    "vendor": "joedolson",
    "ai_description": "Unauthenticated Information Disclosure (IDOR) via Multisite switch_to_blog in My Calendar WordPress plugin",
    "ai_severity": "High",
    "ai_vendor": "Joe Dolson",
    "ai_product": "My Calendar",
    "ai_version": "3.7.6 and below",
    "ai_score": 8.8
}