---
id: CVE-2026-19902
title: >-
  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
  escapin…
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
  escapin…
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'
cwe:
  - CWE-79
vendor: spacetime
product: Ad Inserter – Ad Manager & AdSense Ads
affected:
  - ad_inserter_ad_manager_adsense_ads <= 2.8.18
published: '2026-10-01'
updated: '2026-10-01'
sourceUpdated: '2026-10-01T08:16:51.580'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-19902'
references:
  - url: >-
      https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13018
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13022
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13025
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/ad-inserter.php#L13093
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/ad-inserter/tags/2.8.18/class.php#L3297
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/changeset/3709957/ad-inserter/trunk/ad-inserter.php
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/changeset?reponame=&new=3709970%40ad-inserter%2Ftags%2F2.8.19&old=3624916%40ad-inserter%2Ftags%2F2.8.18
    label: security@wordfence.com
  - url: >-
      https://www.wordfence.com/threat-intel/vulnerabilities/id/5d632cce-40a9-4969-b213-8370ae75287e?source=cve
    label: security@wordfence.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-01T08:40:11.739Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.