CVE-2026-114709 in Ad Inserter Plugin
Summary
by MITRE • 10/26/2026
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Igor Funa Ad Inserter ad-inserter allows Reflected XSS.This issue affects Ad Inserter: from n/a through 2.8.18.
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Analysis
by VulDB Data Team • 10/26/2026
The identified security flaw represents a classic instance of improper neutralization of input during web page generation, commonly categorized under the Cross-Site Scripting (XSS) vulnerability class. Specifically, this issue manifests as a Reflected XSS within the Ad Inserter plugin developed by Igor Funa. The vulnerability exists in versions ranging from n/a through 2.8.18, indicating that any installation of this widely used WordPress advertising management tool operating on these versions is susceptible to exploitation. This type of flaw occurs when an application receives data from a user via HTTP requests and immediately includes that unvalidated or insufficiently validated input into its HTML output without applying appropriate encoding or sanitization mechanisms.
From a technical perspective, the root cause lies in the failure to properly escape special characters such as angle brackets, quotes, ampersands, and other symbols that hold significance within HTML contexts. When an attacker crafts a malicious URL containing embedded JavaScript code or event handlers, the vulnerable parameter accepts this input directly into the page structure. Because the server reflects this input back to the user's browser without neutralization, the web browser interprets the injected script as part of the legitimate webpage content and executes it within the context of the site. This execution environment grants the malicious script access to all cookies, session tokens, local storage data, and other sensitive information associated with the current domain due to same-origin policy constraints.
The operational impact of this vulnerability is significant for both end-users and website administrators. For visitors, successful exploitation allows an attacker to perform actions on behalf of the victim without their knowledge or consent. This can include stealing session cookies to hijack user accounts, redirecting users to phishing sites designed to harvest credentials, defacing the visual appearance of the site, or deploying further malware through drive-by download techniques if combined with other vulnerabilities. For administrators, the presence of this vulnerability undermines trust in the platform and exposes sensitive administrative data if an attacker can trick a logged-in administrator into clicking a malicious link while authenticated. The reflected nature means that exploitation typically requires social engineering to lure victims to a specially crafted URL, but it remains highly effective due to its simplicity and direct execution capability.
In terms of industry standards classification, this vulnerability aligns with CWE-79: Improper Neutralization of Input During Web Page Generation (Cross-site Scripting). More specifically, the reflected variant corresponds to subcategories often associated with input validation failures where output encoding is omitted. Within the MITRE ATT&CK framework, this activity maps to T1059.007: JavaScript, which falls under Command and Scripting Interpreter techniques used by adversaries to execute code on target systems. The exploitation vector typically involves T1189: Drive-by Compromise or T1204: User Execution, as the victim must interact with a malicious link for the script to trigger in their browser context.
Mitigation strategies should focus primarily on immediate patching and robust input validation practices. Website administrators running Ad Inserter versions up to 2.8.18 are strongly advised to upgrade to the latest stable release where this vulnerability has been addressed by the developer. The fix likely involves implementing strict output encoding, such as HTML entity encoding for all user-supplied data before it is rendered in the browser context. Additionally, developers should enforce Content Security Policy (CSP) headers which restrict the sources from which scripts can be loaded and executed, thereby mitigating the impact of any remaining XSS flaws by preventing inline script execution unless explicitly allowed. Regular security audits and code reviews focusing on input handling are essential to prevent similar issues in future updates or other plugins integrated into the WordPress ecosystem.