CVE-2026-77186: joedolson my calendar – accessible event manager Cross-site Scripting

Vulnerability summary

CVE-2026-77186 is a medium (CVSS 6.4) Cross-site Scripting vulnerability in joedolson my calendar – accessible event manager. EPSS estimates a 0.36% chance of exploitation in the next 30 days, higher than 27.8% of scored vulnerabilities. Fixed in 3.8.4.

Timeline

1. 09-09-2026
   PublishedVulnerability first disclosed.
2. 09-09-2026
   Last modifiedVulnerability information updated.

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.

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.