CVE-2026-9838ICS Calendar <= 12.0.9 - Reflected Cross-Site Scripting via 'htmltagtitle' Parameter
Updated under an hour ago ()
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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.
- CVSS
- 6.1 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- Weakness (CWE)
- CWE-79
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Wordfence
- NVD analysis
- Deferred
- Record last updated
- Jul 10, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
room34 ICS Calendar room34:ics_calendar (from the name) | through 12.0.9 | CNA record |
References
- https://www.wordfence.com/threat-intel/vulnerabilities/id/a4d91b01-5034-42b5-857f-c66c875dd562?source=cve
- https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.8.4/templates/calendar-month.php#L40
- https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.8.4/r34ics-ajax.php#L33
- https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.8.4/r34ics-ajax.php#L53
- https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.8.4/r34ics-ajax.php#L72
- https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.5.2/templates/calendar-month.php#L40
- https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.5.2/r34ics-ajax.php#L33
- https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.5.2/r34ics-ajax.php#L53
- https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.5.2/r34ics-ajax.php#L72
- https://plugins.trac.wordpress.org/changeset?reponame=&old=3563728%40ics-calendar&new=3563728%40ics-calendar
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.