CVE-2026-9838 Details
Description
The ICS Calendar plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'htmltagtitle' parameter in all versions up to, and including, 12.0.9 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. The vulnerability is reachable via the unauthenticated wp_ajax_nopriv_r34ics_ajax AJAX action, which accepts attacker-controlled js_args values merged over stored shortcode configuration without nonce verification, allowing the htmltagtitle key to bypass the normal shortcode allowlist check.
A reflected cross-site scripting vulnerability has been identified in the ICS Calendar plugin for WordPress, affecting all versions through 12.0.9. This vulnerability arises from inadequate input sanitization and output escaping, allowing unauthenticated attackers to inject arbitrary web scripts. The exploitation occurs via the 'htmltagtitle' parameter, accessed through the unauthenticated 'wp_ajax_nopriv_r34ics_ajax' AJAX action. This action merges attacker-controlled 'js_args' values with stored shortcode configuration, bypassing normal security checks and enabling the injection of malicious scripts that could be executed if a user is tricked into clicking a link.
Users are advised to update the ICS Calendar plugin to version 12.0.9.2 or later.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Jul 10, 2026CISA-ADP
Assessed Jul 10, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-79 | Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| ICS Calendar | <= 12.0.9 (semver) |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 10, 2026 | CVE Modified | CISA-ADP |
| Jul 10, 2026 | New CVE Received | [email protected] |