CVE-2025-46499 in PayPal Express Checkout Plugin
Summary
by MITRE • 04/24/2025
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in hccoder PayPal Express Checkout allows Stored XSS. This issue affects PayPal Express Checkout: from n/a through 2.1.2.
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Analysis
by VulDB Data Team • 04/24/2025
This vulnerability represents a critical cross-site scripting flaw that enables stored XSS attacks within the hccoder PayPal Express Checkout plugin. The weakness occurs during the web page generation process where user input fails to be properly sanitized or escaped before being rendered in HTML output. The vulnerability specifically affects versions of the PayPal Express Checkout plugin ranging from an unspecified version through 2.1.2, indicating a broad attack surface that could impact numerous installations. This type of vulnerability falls under CWE-79 which defines improper neutralization of input during web page generation as a primary weakness leading to XSS attacks. The stored nature of this vulnerability means that malicious scripts can be permanently injected into the application's database or storage mechanisms, allowing attackers to execute malicious code against users who subsequently view the compromised content. The attack vector typically involves an attacker submitting malicious input through forms or API endpoints that are then stored and later served to other users without proper sanitization.
The operational impact of this vulnerability extends beyond simple script execution as it can enable attackers to hijack user sessions, steal sensitive information, perform unauthorized transactions, or redirect users to malicious websites. In the context of e-commerce platforms like PayPal Express Checkout, this represents a severe threat to both merchant and customer security as attackers could potentially access payment information, user credentials, or manipulate transaction data. The vulnerability creates a persistent threat where malicious payloads remain active until manually removed from the system, making it particularly dangerous for long-term exploitation. According to ATT&CK framework, this vulnerability maps to T1531 - Account Access Removal and T1059.001 - Command and Scripting Interpreter, as attackers can leverage the stored XSS to execute malicious commands and maintain persistent access to compromised systems.
Mitigation strategies for this vulnerability should include immediate patching of affected versions to the latest stable release where the XSS flaw has been addressed. Input validation and output escaping mechanisms must be strengthened to ensure all user-supplied data is properly sanitized before being processed or stored in the database. Implementing Content Security Policy headers can provide additional protection against XSS attacks by restricting the sources from which scripts can be loaded. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other components of the application stack. Organizations should also implement web application firewalls to detect and block malicious input attempts. The remediation process must include thorough testing to ensure that the patch does not introduce regressions in functionality while maintaining the security improvements. Security monitoring should be enhanced to detect unusual patterns in user input or unexpected script execution that could indicate exploitation attempts. Additionally, developers should follow secure coding practices such as implementing proper input validation, using parameterized queries, and employing automated security scanning tools during the development lifecycle to prevent similar vulnerabilities from being introduced in future releases.