CVE-2026-40308

My Calendar < 3.7.7 - Unauthenticated Denial of Service

2026-04-16 00:00

Strategic Overview

Status: Patched in 3.7.7
Affected Plugin: My Calendar – Accessible Event Manager
Affected Version: < 3.7.7
CVSS: 5.3Medium
Weakness type: CWE-639 · Authorization Bypass Through User-Controlled Key
CVE: CVE-2026-40308

View all My Calendar – Accessible Event Manager vulnerabilities

At a glance

CVE-2026-40308 is a medium-severity Authorization Bypass Through User-Controlled Key vulnerability in the My Calendar WordPress plugin, affecting versions < 3.7.7. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 3.7.7; sites on affected versions should update now. Disclosed April 2026, reported by minhi1.

Vulnerability Overview

The My Calendar – Accessible Event Manager plugin for WordPress is vulnerable to Denial of Service in all versions up to 3.7.7 (exclusive). This makes it possible for unauthenticated attackers to trigger a fatal error.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.

CWE-639: Authorization Bypass Through User-Controlled Key

Reaching this weakness in My Calendar < 3.7.7 takes no account at all. Authorization bypass through a user-controlled key, often called insecure direct object reference, means the application looks up a record by an identifier from the request without checking that the caller owns it.

Changing a number in the request is enough to read or modify other users' records, which on commerce and membership sites means customer data. For My Calendar the fix is 3.7.7: builds < 3.7.7 are affected, anything from 3.7.7 onward is not.

Remediation

Update to version 3.7.7, or a newer patched version

How does WordSec protect against this?

This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: My Calendar 3.7.7 closes this, and updating the plugin is the step that ends it.

Login Security
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-40308 https://www.wordfence.com/threat-intel/vulnerabilities/id/9082adc5-508d-47ac-a74a-868e2600e3d6 https://nvd.nist.gov/vuln/detail/CVE-2026-40308

Related records

Same weakness class

5.3CVE-2026-11896: My Calendar IDORCVE-2026-11896

Other vulnerabilities in My Calendar – Accessible Event Manager

CVSS Vector

5.3

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityLow

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