CVE-2025-49390 identifies a Stored Cross-Site Scripting (XSS) vulnerability in the christophrado Cookie Notice & Consent plugin, affecting all versions up to and including 1.6.4. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, which allows malicious scripts to be stored and later executed in the context of users visiting the affected site. This type of vulnerability is particularly dangerous because the malicious payload persists on the server and can affect multiple users without requiring repeated attacker interaction. The CVSS 3.1 base score of 5.4 reflects a medium severity, with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), requiring privileges (PR:L), user interaction (UI:R), and a scope change (S:C). The impact affects confidentiality and integrity (C:L/I:L) but not availability (A:N). Exploitation requires an attacker to have some level of authenticated access to inject the payload and relies on victim users interacting with the malicious content. Although no known exploits are currently reported in the wild, the vulnerability poses a risk to websites using this plugin for cookie consent management, a common feature for compliance with privacy regulations. The lack of available patches at the time of reporting necessitates immediate attention to input validation and output encoding practices. Additionally, deploying Content Security Policy (CSP) headers can mitigate the impact of potential XSS attacks by restricting script execution. Organizations should monitor for updates from the vendor and apply patches promptly once released.

For European organizations, this vulnerability can lead to unauthorized script execution within users' browsers, potentially resulting in session hijacking, theft of sensitive information such as cookies or personal data, and manipulation of website content. Given the plugin’s role in managing cookie consent, attackers could exploit this to undermine user trust and violate data protection regulations like GDPR by exposing or manipulating consent data. The confidentiality and integrity of user data are at risk, which could lead to reputational damage, legal penalties, and loss of customer confidence. The requirement for authenticated access limits the attack surface somewhat, but the necessity of user interaction means phishing or social engineering could be used to trigger the exploit. The absence of availability impact reduces the risk of service disruption but does not diminish the importance of addressing the vulnerability promptly. Organizations with high volumes of web traffic or handling sensitive user data are particularly vulnerable to exploitation attempts.

1. Monitor the vendor’s official channels for the release of a security patch addressing CVE-2025-49390 and apply it immediately upon availability. 2. In the interim, implement strict input validation and output encoding on all user-supplied data processed by the Cookie Notice & Consent plugin to prevent injection of malicious scripts. 3. Deploy a robust Content Security Policy (CSP) header that restricts the execution of inline scripts and limits sources of executable scripts to trusted domains. 4. Conduct regular security audits and penetration testing focusing on XSS vulnerabilities in web applications, especially those involving third-party plugins. 5. Educate authenticated users about the risks of interacting with suspicious content and implement multi-factor authentication to reduce the risk of compromised credentials. 6. Consider temporarily disabling or replacing the vulnerable plugin with an alternative that has a strong security track record until a patch is available. 7. Review and enhance web application firewall (WAF) rules to detect and block XSS attack patterns targeting the affected plugin.