CVE-2026-0557 is a stored Cross-Site Scripting (XSS) vulnerability identified in the WP Data Access plugin for WordPress, a no-code app builder that facilitates creation of tables, forms, charts, and maps. The vulnerability exists in all versions up to and including 5.5.63, due to improper neutralization of user-supplied input in the 'wpda_app' shortcode. Specifically, the plugin fails to adequately sanitize and escape attributes provided by authenticated users with contributor-level or higher access. This flaw allows these users to inject arbitrary JavaScript code into pages, which is then stored and executed in the browser context of any user who visits the affected page. The attack vector is network-based, with low complexity, requiring only contributor-level privileges and no user interaction for the malicious script to execute. The vulnerability impacts confidentiality and integrity by enabling session hijacking, credential theft, or unauthorized actions performed in the context of the victim user. Availability is not directly impacted. The CVSS 3.1 score is 6.4, reflecting medium severity. No patches or known exploits are currently reported, but the vulnerability's presence in a widely used WordPress plugin makes it a notable risk. The scope is limited to WordPress sites using this plugin and having contributors with publishing rights. The vulnerability is classified under CWE-79, indicating improper input neutralization during web page generation.

For European organizations, this vulnerability poses a moderate risk primarily to websites and web applications built on WordPress that utilize the WP Data Access plugin. Exploitation could lead to unauthorized script execution in users' browsers, resulting in session hijacking, theft of sensitive data such as cookies or credentials, and potential privilege escalation if administrative users are targeted. This could compromise the integrity of organizational websites, damage reputation, and lead to data breaches. Organizations with collaborative content creation workflows involving contributors are particularly vulnerable. The impact is heightened for sectors relying heavily on WordPress for customer engagement, such as e-commerce, media, education, and government portals. While availability is not directly affected, the indirect consequences of data compromise and trust erosion can be significant. Given the medium severity and ease of exploitation by authenticated users, organizations must assess their exposure and implement controls to prevent exploitation.

1. Monitor for and apply official patches or updates from the WP Data Access plugin vendor as soon as they become available. 2. Restrict contributor-level permissions to trusted users only and review user roles regularly to minimize the risk of malicious input. 3. Implement strict input validation and output encoding at the application level, especially for user-supplied attributes in shortcodes or similar features. 4. Deploy a Web Application Firewall (WAF) with rules to detect and block XSS payloads targeting WordPress plugins. 5. Conduct regular security audits and penetration testing focusing on WordPress plugins and user-generated content. 6. Educate content contributors about security best practices and the risks of injecting untrusted content. 7. Consider disabling or limiting the use of the 'wpda_app' shortcode if it is not essential to reduce the attack surface. 8. Monitor logs for unusual activity or script injection attempts related to the plugin. 9. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. 10. Backup WordPress sites regularly to enable quick restoration in case of compromise.