---
id: CVE-2026-77186
title: >-
  The My Calendar – Accessible Event Manager plugin for WordPress is vulnerable
  to Stored Cross-Site Scripting via 'fallback' Shortcode Attribute in all
  versions up to, and including, 3.8.3 due to insufficient input sanitization
  and output…
summary: >-
  The My Calendar – Accessible Event Manager plugin for WordPress is vulnerable
  to Stored Cross-Site Scripting via 'fallback' Shortcode Attribute in all
  versions up to, and including, 3.8.3 due to insufficient input sanitization
  and output…
severity: medium
cvss: 6.4
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N'
cwe:
  - CWE-79
vendor: joedolson
product: My Calendar – Accessible Event Manager
affected:
  - my_calendar_accessible_event_manager <= 3.8.3
published: '2026-09-09'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T15:33:34.467'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77186'
references:
  - url: >-
      https://github.com/joedolson/my-calendar/commit/89bbf7314fac84cdb89e520e8b7b6d69eee8dd3c
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/my-calendar/trunk/my-calendar-shortcodes.php#L114
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/my-calendar/trunk/my-calendar-widgets.php#L272
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/my-calendar/trunk/my-calendar.php#L556
    label: security@wordfence.com
  - url: >-
      https://www.wordfence.com/threat-intel/vulnerabilities/id/62c8fb1f-6cba-43cc-8aca-70812c29a63d?source=cve
    label: security@wordfence.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-09T13:12:19.352858Z'
ingestedAt: '2026-09-09T03:58:58.113Z'
epss: 0.00356
epssPercentile: 0.26556
---

## Overview

The My Calendar – Accessible Event Manager plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'fallback' Shortcode Attribute in all versions up to, and including, 3.8.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The bypass relies on hex-encoded shortcode attribute payloads (e.g. \x3cscript\x3e), which wp_kses_post cannot strip on save because they appear as literal backslash sequences rather than real HTML tags; WordPress core's shortcode_parse_atts() then calls stripcslashes() at render time, decoding the escapes into real angle brackets before they reach the unescaped sink.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.