CVE-2026-119468 in Noptin Plugin
Summary
by MITRE • 11/04/2026
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Noptin Newsletter Team Noptin newsletter-optin-box allows Stored XSS.This issue affects Noptin: from n/a through 4.4.2.
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Analysis
by VulDB Data Team • 11/04/2026
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 is a Stored XSS vulnerability located within the Noptin newsletter-optin-box component used by the Noptin Newsletter plugin for WordPress environments. Unlike reflected XSS attacks where malicious scripts are executed immediately via user input in a URL or form submission that does not persist, stored vulnerabilities involve data being saved on the target server and subsequently served to other users. In this context, an attacker can inject malicious JavaScript code into fields intended for newsletter subscription forms or related configuration inputs. Because Noptin versions ranging from n/a through 4.4.2 fail to adequately sanitize these inputs before storing them in the database, the injected script becomes part of the persistent content stored on the server.
When a legitimate user visits a page containing this compromised opt-in box, their browser retrieves the malicious payload along with the rest of the webpage and executes it within the context of the Noptin domain. This execution occurs without any additional interaction required from the victim beyond viewing the page, which significantly lowers the barrier for exploitation compared to other attack vectors. The lack of proper output encoding or input validation allows the script to run in a privileged context relative to the user's session cookies and local storage. Consequently, this vulnerability enables attackers to perform actions on behalf of the authenticated users, steal sensitive information such as session tokens or credentials, deface websites, or redirect users to malicious sites designed for phishing attacks.
From an industry standard perspective, this flaw aligns directly with CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'). The specific nature of the attack falls under MITRE ATT&CK technique T1059.007, which refers to JavaScript as a client-side script execution mechanism. Furthermore, because it involves stored data leading to persistent impact on multiple users, it also relates to CWE-83: Stored Cross-Site Scripting in some taxonomies that distinguish between reflected and stored variants explicitly. The persistence of the payload means that even if the initial injection point is patched or removed from user view, previously injected scripts may continue to execute for any new visitors until the database entries are manually cleaned or overwritten by legitimate updates.
The operational impact of this vulnerability extends beyond immediate data theft. It can lead to severe reputational damage for website owners who host vulnerable instances of Noptin, as their sites become vectors for distributing malware or phishing content to unsuspecting visitors. Additionally, attackers may use the compromised session context to escalate privileges if they gain access to administrative panels through cookie hijacking, potentially leading to full site compromise and defacement. The widespread adoption of WordPress plugins like Noptin means that a successful exploit could affect thousands of websites simultaneously, creating a large-scale attack surface for coordinated campaigns targeting small-to-medium business sites or personal blogs that may lack robust security monitoring.
Mitigation strategies must focus on both immediate remediation and long-term defensive coding practices. The primary recommendation is to upgrade the Noptin Newsletter plugin to version 4.4.3 or later, where this vulnerability has been addressed by developers through improved input sanitization and output encoding mechanisms. For organizations unable to update immediately due to compatibility concerns with other plugins, implementing a Web Application Firewall (WAF) can provide temporary protection by filtering out known XSS payloads in HTTP requests before they reach the application logic. Additionally, administrators should audit existing database entries for any suspicious script tags or encoded JavaScript that may have been injected prior to patching and remove them manually.
To prevent future occurrences of similar vulnerabilities, developers must adhere strictly to secure coding guidelines such as those outlined in OWASP Secure Coding Practices. This includes ensuring that all user-supplied data is validated against a whitelist of expected characters before storage and applying context-sensitive output encoding when rendering data back into HTML documents. Implementing Content Security Policy (CSP) headers can also mitigate the impact of successful XSS attacks by restricting the sources from which scripts are allowed to execute, thereby preventing inline script execution even if an injection succeeds. Regular security audits and penetration testing should be integrated into the development lifecycle to identify such flaws before deployment in production environments.