CVE-2026-19055 Overview
CVE-2026-19055 is a reflected Cross-Site Scripting (XSS) vulnerability [CWE-79] in the ProSolution WP Client WordPress plugin versions before 2.0.11. The plugin fails to sanitize and escape several parameters before reflecting them into HTML attributes on its public pages. Attackers can craft malicious URLs that execute arbitrary JavaScript in the browser of any visitor who follows the link, including logged-in administrators. Successful exploitation can lead to session theft, administrative account takeover, and unauthorized actions performed in the context of the victim.
Critical Impact
Attackers can execute arbitrary JavaScript in an administrator's browser, enabling session hijacking and privileged actions against the WordPress site.
Affected Products
- ProSolution WP Client WordPress plugin versions before 2.0.11
- WordPress sites running the vulnerable plugin on public-facing pages
- Any user, including administrators, browsing affected sites while authenticated
Discovery Timeline
- 2026-08-19 - CVE-2026-19055 published to NVD
- 2026-08-19 - Last updated in NVD database
Technical Details for CVE-2026-19055
Vulnerability Analysis
The ProSolution WP Client plugin exposes public-facing pages that accept parameters from the HTTP request and embed them directly into HTML attributes. The plugin does not apply output escaping routines such as esc_attr() before rendering these values. An attacker who crafts a URL containing malicious payload characters can break out of the intended attribute context and inject arbitrary script content.
The reflected nature of the flaw means the payload is not stored on the server. Exploitation instead requires a victim to click a specially crafted link or visit a page that loads the malicious URL. Because the injected script runs in the security context of the WordPress site, it can access cookies, session tokens, and the DOM of authenticated users.
Root Cause
The root cause is missing input sanitization and output encoding on multiple request parameters reflected into HTML attributes. The plugin trusts request data without applying WordPress escaping functions appropriate for the attribute context. This maps directly to CWE-79, Improper Neutralization of Input During Web Page Generation.
Attack Vector
Exploitation occurs over the network and requires user interaction. An attacker delivers a crafted link through phishing, social media, or a compromised referrer. When an administrator or other authenticated user opens the link, the injected JavaScript executes with the privileges of that user. Because the vulnerability triggers on public pages, no authentication is required on the attacker side to weaponize the payload.
The vulnerability manifests when tainted query parameters are reflected inside HTML attributes without escaping. See the WPScan Vulnerability Advisory for technical details on the affected parameters.
Detection Methods for CVE-2026-19055
Indicators of Compromise
- Web server access logs containing query parameters with encoded script tags, onerror, onload, or javascript: schemes targeting ProSolution WP Client endpoints
- Unexpected outbound requests from administrator browsers to attacker-controlled domains following a click on an external link
- Newly created WordPress administrator accounts or modified user roles without a corresponding legitimate change
Detection Strategies
- Inventory WordPress installations and identify sites running ProSolution WP Client below version 2.0.11
- Deploy web application firewall rules that flag reflected XSS payloads in query strings on plugin URLs
- Monitor referrer headers and click telemetry for administrators arriving at plugin pages from external domains
Monitoring Recommendations
- Enable and centralize WordPress audit logs to track authentication events and privilege changes
- Alert on anomalous admin-ajax or REST API calls originating from administrator sessions shortly after external link clicks
- Review Content Security Policy (CSP) violation reports for inline script executions on plugin-rendered pages
How to Mitigate CVE-2026-19055
Immediate Actions Required
- Update the ProSolution WP Client plugin to version 2.0.11 or later on all WordPress installations
- Force a logout of all active administrator sessions and rotate credentials if compromise is suspected
- Review recent WordPress user, role, and content changes for unauthorized modifications
Patch Information
Upgrade the ProSolution WP Client plugin to version 2.0.11 or later. The fixed release adds proper sanitization and escaping of the affected parameters before they are reflected into HTML attributes. Refer to the WPScan Vulnerability Advisory for advisory details.
Workarounds
- Deactivate the ProSolution WP Client plugin until it can be upgraded to 2.0.11
- Deploy a web application firewall rule blocking requests to plugin endpoints that contain script-like payloads in query parameters
- Enforce a strict Content Security Policy that disallows inline scripts and restricts script sources to trusted origins
- Train administrators to avoid clicking untrusted links while authenticated to the WordPress admin console
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
