CVE-2025-64264 is a stored Cross-site Scripting (XSS) vulnerability identified in the Aman Popup addon for Ninja Forms, a popular WordPress form plugin. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, which allows attackers to inject malicious scripts that are stored and later executed in the context of users visiting the affected site. This persistent XSS can be exploited when an attacker with high privileges (PR:H) submits crafted input that is not properly sanitized or escaped, leading to script execution when other users interact with the popup or form elements. The vulnerability requires user interaction (UI:R), such as visiting a page or triggering the popup, to activate the malicious payload. The CVSS v3.1 score of 5.9 (medium severity) reflects the network attack vector (AV:N), low attack complexity (AC:L), but the need for high privileges and user interaction. The scope is changed (S:C), indicating that exploitation can affect resources beyond the vulnerable component, impacting confidentiality, integrity, and availability to a limited extent (C:L/I:L/A:L). No patches or known exploits are currently reported, but the vulnerability affects all versions up to and including 3.5.1 of the addon. Stored XSS vulnerabilities are particularly dangerous as they can facilitate session hijacking, credential theft, defacement, or distribution of malware through trusted websites.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on WordPress sites with Ninja Forms and the Aman Popup addon installed. Successful exploitation could allow attackers to execute arbitrary JavaScript in the context of users, potentially leading to theft of sensitive data such as session cookies, user credentials, or personally identifiable information (PII). This can result in unauthorized access, data breaches, or further compromise of internal systems. The integrity of web content can be undermined, damaging organizational reputation and trust. Availability impacts may arise if injected scripts disrupt normal site functionality or cause denial-of-service conditions. Given the widespread use of WordPress in Europe and the popularity of Ninja Forms, sectors such as e-commerce, government portals, and healthcare websites are at risk. The requirement for high privileges to inject malicious input somewhat limits the attack surface but does not eliminate risk, especially if administrative accounts are compromised or insider threats exist.

1. Apply patches or updates from the Aman Popup addon vendor as soon as they become available to address the vulnerability directly. 2. Until patches are released, restrict administrative and high-privilege user access to trusted personnel only and enforce strong authentication mechanisms to reduce the risk of privilege abuse. 3. Implement a robust Content Security Policy (CSP) to limit the execution of unauthorized scripts and reduce the impact of XSS attacks. 4. Use web application firewalls (WAFs) with rules designed to detect and block XSS payloads targeting Ninja Forms and related plugins. 5. Conduct regular security audits and code reviews of customizations involving Ninja Forms and its addons to ensure proper input validation and output encoding. 6. Educate site administrators and users about phishing and social engineering risks that could lead to privilege escalation or injection of malicious content. 7. Monitor logs and user activity for unusual behavior indicative of exploitation attempts. 8. Consider disabling or replacing the vulnerable addon if immediate patching is not feasible.