Ad Inserter - Security Vulnerability (CVE-2026-19902)
CVE-2026-19902
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.
CVE-2026-19902
MEDIUM
CVSS 6.1
Published 2026-10-01
Updated 2026-10-01
AI Risk Elevated (67/100)
Active Exploit: No strong signal
Published Exploit: No public exploit references
Priority: P3 Priority
Severity Band
MEDIUM
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Affected Components
1
Reference Links
8
AI Risk Engine
Elevated (67/100)
Exploitability
High
Active Exploitation
No strong signal
Published Exploit Status
No public exploit references
AI Context
Machine-generated threat intelligence
AI
Updated 6 days ago
AI enriched 6 days ago (2026-10-01 18:22 UTC)
Technical 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…
Potential Impact
Severity is MEDIUM (CVSS 6.1). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.
Exploitability Assessment
Exploitability is assessed as High based on remote code execution potential, low-bar exploit prerequisites.
Primary risk drivers: remote code execution potential, low-bar exploit prerequisites
Mitigation Recommendations
Validate affected product versions, prioritize patching, and monitor references for vendor remediation guidance. If immediate patching is not possible, apply compensating controls and limit exposure of vulnerable surfaces.
Detection & Monitoring
Track authentication anomalies, unexpected file writes, and suspicious plugin API activity around affected components.
Business Impact Lens
AI risk score 67/100 (Elevated, High) with priority P3 Priority. Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.
