CVE-2025-6324 identifies a DOM-based Cross-site Scripting (XSS) vulnerability in the MatrixAddons Easy Invoice software, affecting all versions up to and including 2.0.9. This vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, which allows malicious scripts to be injected and executed within the victim's browser environment. Unlike reflected or stored XSS, DOM-based XSS occurs entirely on the client side, where the malicious payload is executed as a result of unsafe manipulation of the Document Object Model (DOM) by the web application’s JavaScript code. This can lead to unauthorized actions such as session hijacking, credential theft, or unauthorized transactions if an attacker tricks a user into visiting a crafted URL or interacting with malicious content. The vulnerability does not require authentication, increasing its risk profile, and no public exploits have been reported yet. Easy Invoice is a billing and invoicing solution used primarily by small and medium enterprises (SMEs) to manage financial documents, making the confidentiality and integrity of data critical. The lack of a CVSS score indicates the need for a manual severity assessment. The vulnerability was reserved in June 2025 and published in December 2025, but no patch links are currently available, highlighting the urgency for vendors and users to prioritize remediation once patches are released.

For European organizations, this vulnerability poses a significant risk to the confidentiality and integrity of invoicing and financial data. Successful exploitation could allow attackers to execute arbitrary scripts in users’ browsers, potentially leading to session hijacking, unauthorized access to sensitive financial information, and fraudulent invoice manipulation. This could result in financial losses, regulatory non-compliance (especially under GDPR), and reputational damage. SMEs, which form a large part of the European economy and are common users of Easy Invoice, may be particularly vulnerable due to limited cybersecurity resources. Additionally, the ability to exploit this vulnerability without authentication and user interaction (beyond visiting a malicious link) increases the attack surface. The absence of known exploits in the wild provides a window for proactive defense, but also means organizations should not underestimate the threat given the ease of exploitation and potential impact.

1. Monitor MatrixAddons communications closely for official patches addressing CVE-2025-6324 and apply them immediately upon release. 2. Until patches are available, implement strict input validation and output encoding on all user-supplied data within the Easy Invoice application, focusing on areas where DOM manipulation occurs. 3. Deploy Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the risk of XSS exploitation. 4. Educate users about the risks of clicking on suspicious links, especially those related to invoicing or financial communications. 5. Conduct regular security assessments and penetration testing focusing on client-side vulnerabilities in web applications. 6. Consider using web application firewalls (WAFs) with custom rules to detect and block XSS attack patterns targeting Easy Invoice. 7. Review and harden browser security settings and encourage the use of modern browsers with built-in XSS protections. 8. Implement multi-factor authentication (MFA) to reduce the impact of session hijacking if exploitation occurs.