{"id":"CVE-2026-19902","aliases":["EUVD-2026-90545","GHSA-298r-885r-pj27"],"status":"published","title":"Ad Inserter \u003c= 2.8.18 - Reflected Cross-Site Scripting via {search-query} Dynamic Tag (Referer Header)","description":"The Ad Inserter – Ad Manager \u0026 AdSense Ads plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the Referer header in all versions up to, and including, 2.8.18 due to insufficient input sanitization and output escaping on the '{search-query}' dynamic tag. When an ad block's code contains that tag, replace_ai_tags() reads $_SERVER['HTTP_REFERER'] and tests it with the regex /[\\.\\/](google|yahoo|bing|ask)\\.[a-z\\.]{2,5}[\\/]/i. The leading [\\.\\/] class matches a literal slash, so any referrer merely containing a segment such as '/google.com/' passes as a search-engine referral; the plugin then percent-decodes the referring query with parse_str() and substitutes the resulting 'q' (or 'p') value into the block via preg_replace() with no escaping. This makes it possible for unauthenticated attackers to execute arbitrary JavaScript in the context of the site for any visitor, including a signed-in administrator, by luring them to an attacker-controlled page that frames or links to any ordinary post. Exploitation requires the site to have an ad block whose code uses the '{search-query}' tag with automatic insertion enabled — a documented plugin feature used as intended.","severity":{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00259,"percentile":0.17724,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-79"],"published":"2026-10-01T07:40:23Z","modified":"2026-10-03T16:16:36Z","products":[{"vendor":"spacetime","product":"ad inserter – ad manager \u0026 adsense ads"}],"references":[{"url":"https://www.wordfence.com/threat-intel/vulnerabilities/id/5d632cce-40a9-4969-b213-8370ae75287e?source=cve"},{"url":"https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13093"},{"url":"https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13018"},{"url":"https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13022"},{"url":"https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13025"},{"url":"https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/class.php#L3297"},{"url":"https://plugins.trac.wordpress.org/changeset?reponame=\u0026new=3709970%40ad-inserter%2Ftags%2F2.8.19\u0026old=3624916%40ad-inserter%2Ftags%2F2.8.18"},{"url":"https://plugins.trac.wordpress.org/changeset/3709957/ad-inserter/trunk/ad-inserter.php"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-19902"},{"url":"https://github.com/advisories/GHSA-298r-885r-pj27"}],"sources":{"cve":[{"id":"CVE-2026-19902","title":"Ad Inserter \u003c= 2.8.18 - Reflected Cross-Site Scripting via {search-query} Dynamic Tag (Referer Header)","description":"The Ad Inserter – Ad Manager \u0026 AdSense Ads plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the Referer header in all versions up to, and including, 2.8.18 due to insufficient input sanitization and output escaping on the '{search-query}' dynamic tag. When an ad block's code contains that tag, replace_ai_tags() reads $_SERVER['HTTP_REFERER'] and tests it with the regex /[\\.\\/](google|yahoo|bing|ask)\\.[a-z\\.]{2,5}[\\/]/i. The leading [\\.\\/] class matches a literal slash, so any referrer merely containing a segment such as '/google.com/' passes as a search-engine referral; the plugin then percent-decodes the referring query with parse_str() and substitutes the resulting 'q' (or 'p') value into the block via preg_replace() with no escaping. This makes it possible for unauthenticated attackers to execute arbitrary JavaScript in the context of the site for any visitor, including a signed-in administrator, by luring them to an attacker-controlled page that frames or links to any ordinary post. Exploitation requires the site to have an ad block whose code uses the '{search-query}' tag with automatic insertion enabled — a documented plugin feature used as intended.","status":"published","published":"2026-10-01T07:40:23.197Z","modified":"2026-10-03T15:42:52.231Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T13:47:17.512524Z"}],"euvd":[{"id":"EUVD-2026-90545","description":"The Ad Inserter – Ad Manager \u0026 AdSense Ads plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the Referer header in all versions up to, and including, 2.8.18 due to insufficient input sanitization and output escaping on the '{search-query}' dynamic tag. When an ad block's code contains that tag, replace_ai_tags() reads $_SERVER['HTTP_REFERER'] and tests it with the regex /[\\.\\/](google|yahoo|bing|ask)\\.[a-z\\.]{2,5}[\\/]/i. The leading [\\.\\/] class matches a literal slash, so any referrer merely containing a segment such as '/google.com/' passes as a search-engine referral; the plugin then percent-decodes the referring query with parse_str() and substitutes the resulting 'q' (or 'p') value into the block via preg_replace() with no escaping. This makes it possible for unauthenticated attackers to execute arbitrary JavaScript in the context of the site for any visitor, including a signed-in administrator, by luring them to an attacker-controlled page that frames or links to any ordinary post. Exploitation requires the site to have an ad block whose code uses the '{search-query}' tag with automatic insertion enabled — a documented plugin feature used as intended.","status":"published","published":"2026-10-01T07:40:23Z","modified":"2026-10-03T15:42:52Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T17:27:40.640907Z"}],"ghsa":[{"id":"GHSA-298r-885r-pj27","title":"The Ad Inserter – Ad Manager \u0026 AdSense Ads plugin for WordPress is vulnerable to Reflected Cross...","description":"The Ad Inserter – Ad Manager \u0026 AdSense Ads plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the Referer header in all versions up to, and including, 2.8.18 due to insufficient input sanitization and output escaping on the '{search-query}' dynamic tag. When an ad block's code contains that tag, replace_ai_tags() reads $_SERVER['HTTP_REFERER'] and tests it with the regex /[\\.\\/](google|yahoo|bing|ask)\\.[a-z\\.]{2,5}[\\/]/i. The leading [\\.\\/] class matches a literal slash, so any referrer merely containing a segment such as '/google.com/' passes as a search-engine referral; the plugin then percent-decodes the referring query with parse_str() and substitutes the resulting 'q' (or 'p') value into the block via preg_replace() with no escaping. This makes it possible for unauthenticated attackers to execute arbitrary JavaScript in the context of the site for any visitor, including a signed-in administrator, by luring them to an attacker-controlled page that frames or links to any ordinary post. Exploitation requires the site to have an ad block whose code uses the '{search-query}' tag with automatic insertion enabled — a documented plugin feature used as intended.","status":"published","published":"2026-10-01T09:30:33Z","modified":"2026-10-01T09:30:42Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:12:39.998127Z"}],"nvd":[{"id":"CVE-2026-19902","description":"The Ad Inserter – Ad Manager \u0026 AdSense Ads plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the Referer header in all versions up to, and including, 2.8.18 due to insufficient input sanitization and output escaping on the '{search-query}' dynamic tag. When an ad block's code contains that tag, replace_ai_tags() reads $_SERVER['HTTP_REFERER'] and tests it with the regex /[\\.\\/](google|yahoo|bing|ask)\\.[a-z\\.]{2,5}[\\/]/i. The leading [\\.\\/] class matches a literal slash, so any referrer merely containing a segment such as '/google.com/' passes as a search-engine referral; the plugin then percent-decodes the referring query with parse_str() and substitutes the resulting 'q' (or 'p') value into the block via preg_replace() with no escaping. This makes it possible for unauthenticated attackers to execute arbitrary JavaScript in the context of the site for any visitor, including a signed-in administrator, by luring them to an attacker-controlled page that frames or links to any ordinary post. Exploitation requires the site to have an ad block whose code uses the '{search-query}' tag with automatic insertion enabled — a documented plugin feature used as intended.","status":"published","published":"2026-10-01T08:16:51.58Z","modified":"2026-10-03T16:16:36.933Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:12:53.097633Z"}]}}