My Calendar <= 3.8.3 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'fallback' Shortcode Attribute
| CVE | CVE-2026-77186 |
|---|---|
| CVSS | 6.4 (Medium) |
| Publicly Published | September 8, 2026 |
| Last Updated | September 9, 2026 |
| Researcher |
Wordfence PRISM
- Wordfence
|
Description
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.
Learn more about Cross-Site Scripting vulnerabilities and how to prevent them.
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Vulnerability Details for My Calendar – Accessible Event Manager
| Software Type | Plugin |
|---|---|
| Software Slug | my-calendar (view on wordpress.org) |
| Patched? | Yes |
| Remediation | Update to version 3.8.4, or a newer patched version |
| Affected Version |
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| Patched Version |
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Recent vulnerabilities in My Calendar – Accessible Event Manager
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