FKIE_CVE-2026-19902

Vulnerability from fkie_nvd - Published: 2026-10-01 08:16 - Updated: 2026-10-03 16:16
Severity
6.1 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Summary
The Ad Inserter – Ad Manager & 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.
References
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13018
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13022
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13025
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13093
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/class.php#L3297
security@wordfence.comhttps://plugins.trac.wordpress.org/changeset/3709957/ad-inserter/trunk/ad-inserter.php
security@wordfence.comhttps://plugins.trac.wordpress.org/changeset?reponame=&new=3709970%40ad-inserter%2Ftags%2F2.8.19&old=3624916%40ad-inserter%2Ftags%2F2.8.18
security@wordfence.comhttps://www.wordfence.com/threat-intel/vulnerabilities/id/5d632cce-40a9-4969-b213-8370ae75287e?source=cve
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Ad Inserter \u2013 Ad Manager \u0026 AdSense Ads",
          "vendor": "spacetime",
          "versions": [
            {
              "lessThanOrEqual": "2.8.18",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "security@wordfence.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The Ad Inserter \u2013 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 \u0027{search-query}\u0027 dynamic tag. When an ad block\u0027s code contains that tag, replace_ai_tags() reads $_SERVER[\u0027HTTP_REFERER\u0027] 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 \u0027/google.com/\u0027 passes as a search-engine referral; the plugin then percent-decodes the referring query with parse_str() and substitutes the resulting \u0027q\u0027 (or \u0027p\u0027) 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 \u0027{search-query}\u0027 tag with automatic insertion enabled \u2014 a documented plugin feature used as intended."
    }
  ],
  "id": "CVE-2026-19902",
  "lastModified": "2026-10-03T16:16:36.933",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.1,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 2.7,
        "source": "security@wordfence.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-19902",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-03T15:35:45.406125Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-10-01T08:16:51.580",
  "references": [
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13018"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13022"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13025"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13093"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/class.php#L3297"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/changeset/3709957/ad-inserter/trunk/ad-inserter.php"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/changeset?reponame=\u0026new=3709970%40ad-inserter%2Ftags%2F2.8.19\u0026old=3624916%40ad-inserter%2Ftags%2F2.8.18"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/5d632cce-40a9-4969-b213-8370ae75287e?source=cve"
    }
  ],
  "sourceIdentifier": "security@wordfence.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ],
      "source": "security@wordfence.com",
      "type": "Secondary"
    }
  ]
}



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