CVE-2026-0557: WP Data Access Plugin XSS Vulnerability

CVE-2026-0557 Overview

A Stored Cross-Site Scripting (XSS) vulnerability has been identified in the WP Data Access plugin for WordPress. The vulnerability exists in the plugin's wpda_app shortcode functionality in all versions up to and including 5.5.63. Due to insufficient input sanitization and output escaping on user-supplied attributes, authenticated attackers with contributor-level access or above can inject arbitrary web scripts into WordPress pages. These malicious scripts execute whenever any user accesses an affected page, potentially compromising user sessions, stealing credentials, or performing actions on behalf of victims.

Critical Impact

Authenticated attackers with contributor-level access can inject persistent malicious scripts that execute in the browsers of all users who view the compromised pages, enabling session hijacking, credential theft, and phishing attacks.

Affected Products

• WP Data Access plugin for WordPress versions up to and including 5.5.63
• WordPress installations utilizing the wpda_app shortcode functionality
• Any WordPress site with contributor or higher-level user accounts using vulnerable plugin versions

Discovery Timeline

• February 14, 2026 - CVE-2026-0557 published to NVD
• February 18, 2026 - Last updated in NVD database

Technical Details for CVE-2026-0557

Vulnerability Analysis

This Stored Cross-Site Scripting vulnerability stems from improper handling of user-controlled input within the WP Data Access plugin's shortcode processing logic. When users with contributor-level privileges or above create or edit content containing the wpda_app shortcode, the plugin fails to adequately sanitize and escape attribute values before rendering them in the page output.

The vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation), which describes the failure to properly handle special characters that could be interpreted as control characters in the web browser context. The scope is changed (S:C in the CVSS vector), meaning the vulnerable component and the impacted component are different—the WordPress plugin processes the input, but the victim's browser is where the impact occurs.

Root Cause

The root cause lies in the WPDA_App_Container.php file, specifically around lines 151-152 where user-supplied shortcode attributes are processed. The plugin does not implement sufficient input validation or output encoding when handling these attributes, allowing attackers to craft malicious attribute values containing JavaScript code. When these values are rendered in the HTML output without proper escaping, the browser interprets them as executable scripts rather than data content.

Attack Vector

The attack requires an authenticated attacker with at least contributor-level access to the WordPress site. The attacker crafts a post or page containing the wpda_app shortcode with malicious JavaScript embedded in one or more of its attributes. Once the content is published or saved as a draft (depending on WordPress configuration), any user who views the page—including administrators—will have the malicious script executed in their browser context.

This network-based attack does not require user interaction beyond normal page viewing, and the low complexity makes it accessible to attackers with basic technical knowledge. The vulnerability enables both confidentiality and integrity impacts through potential data theft and unauthorized actions performed in the victim's authenticated session.

Detection Methods for CVE-2026-0557

Indicators of Compromise

• Unusual JavaScript code or <script> tags appearing within wpda_app shortcode attributes in WordPress posts or pages
• Unexpected external resource requests originating from pages using the WP Data Access plugin
• Reports of suspicious redirects or pop-ups when users access pages containing the wpda_app shortcode
• Anomalous POST requests or data exfiltration attempts correlated with page views

Detection Strategies

• Implement Content Security Policy (CSP) headers to detect and block inline script execution attempts
• Conduct regular audits of WordPress posts and pages for suspicious shortcode attribute content using pattern matching for XSS payloads
• Enable WordPress audit logging to track content modifications by contributor-level users
• Deploy Web Application Firewall (WAF) rules to identify and alert on common XSS patterns in content submissions

Monitoring Recommendations

• Monitor WordPress database tables (wp_posts, wp_postmeta) for entries containing JavaScript event handlers or script tags within shortcode content
• Set up alerts for unusual patterns in contributor-level user activity, particularly rapid content creation or editing
• Review browser console errors and network traffic anomalies reported by site visitors
• Implement integrity monitoring for WordPress plugin files to detect unauthorized modifications

How to Mitigate CVE-2026-0557

Immediate Actions Required

• Update WP Data Access plugin to version 5.5.64 or later immediately
• Audit all existing content containing wpda_app shortcodes for malicious attribute values
• Review user accounts with contributor-level access or above and remove unnecessary privileges
• Consider temporarily disabling the WP Data Access plugin until the update can be applied

Patch Information

The vulnerability has been addressed in WP Data Access version 5.5.64. The fix implements proper input sanitization and output escaping for user-supplied attributes in the wpda_app shortcode. Technical details of the patch can be reviewed in the WordPress Plugin Source Code. Additional vulnerability information is available in the Wordfence Vulnerability Report.

Workarounds

• Restrict contributor and author-level user accounts from publishing content without editorial review until the patch is applied
• Implement a Web Application Firewall with XSS protection rules to filter malicious input patterns
• Add Content Security Policy headers to prevent inline script execution as a defense-in-depth measure
• Temporarily remove or disable the wpda_app shortcode functionality if immediate patching is not possible

# WordPress CLI command to update the WP Data Access plugin
wp plugin update wp-data-access --version=5.5.64

# Verify the installed version after update
wp plugin get wp-data-access --field=version