CVE-2026-3617 identifies a stored Cross-Site Scripting (XSS) vulnerability in the swergroup Paypal Shortcodes plugin for WordPress, present in all versions up to and including 0.3. The vulnerability stems from the swer_paypal_shortcode() function, which processes shortcode attributes 'amount' and 'name' by extracting them via extract() and shortcode_atts() functions. These attribute values are then directly concatenated into HTML input element value attributes without any escaping functions such as esc_attr(), leading to improper neutralization of input during web page generation (CWE-79). This allows an authenticated attacker with Contributor-level or higher privileges to inject arbitrary JavaScript code into pages or posts containing the shortcode. When other users visit these pages, the malicious script executes in their browsers, potentially leading to session hijacking, defacement, or other client-side attacks. The vulnerability is exploitable remotely over the network without user interaction but requires authentication with low privileges. The CVSS 3.1 base score is 6.4, indicating medium severity, with impact on confidentiality and integrity but no impact on availability. No patches or known exploits have been reported at the time of publication. The vulnerability highlights the importance of proper input sanitization and output escaping in WordPress plugin development, especially when handling user-supplied shortcode attributes that are rendered in HTML contexts.

The primary impact of CVE-2026-3617 is the potential for stored XSS attacks on WordPress sites using the vulnerable Paypal Shortcodes plugin. Attackers with Contributor-level access can inject malicious scripts that execute in the browsers of site visitors, including administrators and other users. This can lead to theft of authentication cookies, session hijacking, unauthorized actions performed on behalf of users, defacement of site content, or distribution of malware. The compromise of user confidentiality and integrity can damage organizational reputation and trust. Although availability is not directly affected, the indirect consequences of such attacks can include site downtime due to remediation efforts or blacklisting by security services. Organizations relying on this plugin for payment integration or donation processing may face increased risk of fraud or data leakage. The vulnerability's requirement for authenticated access limits exposure but does not eliminate risk, especially on sites with multiple contributors or less restrictive user role assignments. Given WordPress's widespread use globally, many organizations could be impacted if they use this plugin without mitigation.

To mitigate CVE-2026-3617, organizations should first check for and apply any official patches or updates released by swergroup for the Paypal Shortcodes plugin. If no patch is available, immediate manual mitigation involves modifying the plugin code to properly escape user-supplied shortcode attributes before output. Specifically, the $name and $amount values should be passed through WordPress's esc_attr() function or equivalent escaping functions before being inserted into HTML attributes. Additionally, review and restrict user roles and permissions to limit Contributor-level access only to trusted users. Implement Web Application Firewall (WAF) rules to detect and block suspicious shortcode attribute inputs containing script tags or event handlers. Regularly audit WordPress plugins for security best practices and consider replacing vulnerable plugins with more secure alternatives. Enable Content Security Policy (CSP) headers to reduce the impact of any injected scripts. Finally, educate site administrators and contributors about the risks of injecting untrusted content and monitor logs for unusual activity related to shortcode usage.