CVE-2026-19902 (GCVE-0-2026-19902)

Vulnerability from cvelistv5 – Published: 2026-10-01 07:40 – Updated: 2026-10-01 07:40
VLAI
Title
Ad Inserter <= 2.8.18 - Reflected Cross-Site Scripting via {search-query} Dynamic Tag (Referer Header)
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.
Severity
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CWE
  • CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
References
Impacted products
Vendor Product Version CPE status
spacetime Ad Inserter – Ad Manager & AdSense Ads Affected: 0 , ≤ 2.8.18 (semver)
guessed Create a notification for this product.
Credits
Yuto Hyakumoto
Show details on NVD website
To clipboard 

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  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Ad Inserter \u2013 Ad Manager \u0026 AdSense Ads",
          "vendor": "spacetime",
          "versions": [
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              "status": "affected",
              "version": "0",
              "versionType": "semver"
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      "credits": [
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          "type": "finder",
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          "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
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            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
            "version": "3.1"
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            }
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      "providerMetadata": {
        "dateUpdated": "2026-10-01T07:40:23.197Z",
        "orgId": "b15e7b5b-3da4-40ae-a43c-f7aa60e62599",
        "shortName": "Wordfence"
      },
      "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"
        }
      ],
      "timeline": [
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          "lang": "en",
          "time": "2026-08-14T19:31:26.000Z",
          "value": "Vendor Notified"
        },
        {
          "lang": "en",
          "time": "2026-09-30T19:33:23.000Z",
          "value": "Disclosed"
        }
      ],
      "title": "Ad Inserter \u003c= 2.8.18 - Reflected Cross-Site Scripting via {search-query} Dynamic Tag (Referer Header)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "b15e7b5b-3da4-40ae-a43c-f7aa60e62599",
    "assignerShortName": "Wordfence",
    "cveId": "CVE-2026-19902",
    "datePublished": "2026-10-01T07:40:23.197Z",
    "dateReserved": "2026-08-14T19:15:32.388Z",
    "dateUpdated": "2026-10-01T07:40:23.197Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
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              {
                "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": "2026-10-01T12:40:28.083",
        "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",
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              "impactScore": 2.7,
              "source": "security@wordfence.com",
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        "published": "2026-10-01T08:16:51.580",
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            "source": "security@wordfence.com",
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            "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",
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                "value": "CWE-79"
              }
            ],
            "source": "security@wordfence.com",
            "type": "Primary"
          }
        ]
      }
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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Nomenclature

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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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