CVE-2026-77186mediumCWE-79

CVE-2026-77186: medium-severity vulnerability in joedolson My Calendar – Accessible Event Manager

My Calendar <= 3.8.3 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'fallback' Shortcode Attribute

Published

Follow this CVE+ Monitor My Calendar – Accessible Event Manager

E-mail alert when it lands in KEV, gets a public PoC or its score goes up.

13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 6.4epss 0.4%
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.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Affected products
joedolson · My Calendar – Accessible Event Manager
Related CVEs — joedolson My Calendar – Accessible Event Manager

In the same product, most dangerous first.

CVE-2026-6854HIGHMy Calendar <= 3.7.8 - Unauthenticated SQL Injection via 'mc_auth' and 'mc_host' ParametersEPSS 1.6%CVE-2026-11896MEDIUMMy Calendar <= 3.7.14 - Insecure Direct Object Reference to Unauthenticated Sensitive Information Disclosure via 'vcal' ParameterEPSS 0.5%CVE-2026-104798CRITICALMy Calendar <= 3.8.7 - Unauthenticated Privilege Escalation to 'mcs' Parameter via Reflected Shortcode Injection into 'above' AttributeEPSS 0.5%CVE-2026-7525MEDIUMMy Calendar <= 3.7.9 - Authenticated (Custom+) Missing Authorization to Unauthorized Event Publication via 'event_approved' ParameterEPSS 0.3%CVE-2026-77187MEDIUMMy Calendar <= 3.8.3 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'before' and 'after' Shortcode AttributesEPSS 0.3%CVE-2026-2355MEDIUMMy Calendar – Accessible Event Manager <= 3.7.3 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode AttributesEPSS 0.3%