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.
CVE-2026-9838
MEDIUMPre-NVD 6.16.1—Trending — 4 sources updated this week
EchelonGraph scoreHIGH confidence
Score 6.1 from GitHub Security Advisory published 2026-07-10. a secondary CVSS source baseline 6.1; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
6.1
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.1Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.1
- EG Score
- 6.1(high)
- EPSS
- 21.5%
- KEV
- Not listed
Published
July 10, 2026
Last Modified
July 10, 2026
References (10)
- security@wordfencehttps://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.5.2/r34ics-ajax.php#L33
- security@wordfencehttps://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.5.2/r34ics-ajax.php#L53
- security@wordfencehttps://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.5.2/r34ics-ajax.php#L72
- security@wordfencehttps://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.5.2/templates/calendar-month.php#L40
- security@wordfencehttps://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.8.4/r34ics-ajax.php#L33
- security@wordfencehttps://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.8.4/r34ics-ajax.php#L53
- security@wordfencehttps://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.8.4/r34ics-ajax.php#L72
- security@wordfencehttps://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.8.4/templates/calendar-month.php#L40
- security@wordfencehttps://plugins.trac.wordpress.org/changeset?reponame=&old=3563728%40ics-calendar&new=3563728%40ics-calendar
- security@wordfencehttps://www.wordfence.com/threat-intel/vulnerabilities/id/a4d91b01-5034-42b5-857f-c66c875dd562?source=cve
Vendor Advisories for CVE-2026-9838(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 18× in last 7d / 18× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 06:50 UTCEG score recompute
- 2026-07-15 06:50 UTCGHSA enrichment
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-14 07:14 UTCEG score recompute
- 2026-07-14 07:14 UTCGHSA enrichment
- 2026-07-13 22:31 UTCEPSS rescore
- 2026-07-13 07:39 UTCEG score recompute
- 2026-07-13 07:39 UTCGHSA enrichment
- 2026-07-13 06:13 UTCEPSS rescore
- 2026-07-12 08:03 UTCEG score recompute
- 2026-07-12 08:03 UTCGHSA enrichment
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-11 08:27 UTCEG score recompute
- 2026-07-11 08:27 UTCGHSA enrichment
- 2026-07-10 08:52 UTCEG score recompute
- 2026-07-10 08:52 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-9838?
CVE-2026-9838 is a medium vulnerability published on July 10, 2026. 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…
When was CVE-2026-9838 disclosed?
CVE-2026-9838 was first published in the National Vulnerability Database on July 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-9838 actively exploited?
CVE-2026-9838 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 21.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-9838?
CVE-2026-9838 has a CVSS v3 base score of 6.1 (NVD).
How do I remediate CVE-2026-9838?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-9838, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-9838
Is Your Infrastructure Affected by CVE-2026-9838?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.