CVE-2026-19797 Overview
CVE-2026-19797 is a Reflected Cross-Site Scripting (XSS) vulnerability in the User Access Manager plugin for WordPress. The flaw affects all versions up to and including 2.3.18. It stems from insufficient input sanitization and output escaping of the tab_group_section parameter. Unauthenticated attackers can inject arbitrary web scripts that execute in a victim's browser when the victim clicks a crafted link. The issue is tracked under CWE-79 and was analyzed by Wordfence.
Critical Impact
Successful exploitation enables session hijacking, credential theft, or administrative action forgery when a logged-in WordPress user clicks an attacker-controlled link.
Affected Products
- User Access Manager plugin for WordPress, versions up to and including 2.3.18
- WordPress sites with the plugin installed and activated
- Administrative interface routes that render the tab_group_section request parameter
Discovery Timeline
- 2026-09-09 - CVE-2026-19797 published to NVD
- 2026-09-09 - Last updated in NVD database
Technical Details for CVE-2026-19797
Vulnerability Analysis
The vulnerability exists in the User Access Manager plugin's backend controller logic. The tab_group_section request parameter is read from user-controlled input and reflected into rendered admin views without adequate sanitization or output escaping. Because the reflection occurs within an authenticated administrative page context, script payloads execute with the privileges of the browsing user.
Relevant code paths are visible in the plugin's ControllerTabNavigationTrait.php, BaseControllerTrait.php, and AdminSettings.php. The fix is captured in the plugin repository changeset 3680890.
Root Cause
The root cause is missing input sanitization on the tab_group_section parameter and missing output escaping when the value is rendered into HTML context. WordPress provides helpers such as sanitize_text_field() for input and esc_attr() or esc_html() for output, but neither category was applied to this parameter path prior to 2.3.18.
Attack Vector
An unauthenticated attacker crafts a URL to a vulnerable admin endpoint with a malicious payload placed in the tab_group_section query parameter. The attacker then delivers that URL to a WordPress administrator via phishing, chat, or a public page. When the target clicks the link while authenticated to WordPress, the injected script executes in the administrator's session. This enables cookie theft, forced privileged actions, or account takeover through admin-scoped requests.
No verified proof-of-concept code is published in the referenced advisory. See the Wordfence advisory for additional analysis.
Detection Methods for CVE-2026-19797
Indicators of Compromise
- Web server access logs containing requests to WordPress admin routes with tab_group_section= values including <script, %3Cscript, onerror=, or javascript: payloads.
- Referrer headers pointing to external domains preceding administrator logins to /wp-admin/.
- Unexpected new administrator accounts, plugin installations, or theme file modifications following an admin session.
Detection Strategies
- Deploy Web Application Firewall (WAF) rules that inspect the tab_group_section parameter for HTML tags, event handlers, and URL-encoded script fragments.
- Enforce a Content Security Policy (CSP) on the WordPress admin interface to block inline script execution and flag violations.
- Correlate outbound requests from administrator browsers with WordPress admin sessions to identify data exfiltration attempts.
Monitoring Recommendations
- Monitor the plugin version in use across all WordPress instances and alert when user-access-manager is below 2.3.19 or the patched release.
- Track high-privilege user activity such as user creation, role changes, and plugin uploads, and correlate with recent admin URL parameters.
- Ingest WordPress and web server logs into a centralized analytics platform for retention and query.
How to Mitigate CVE-2026-19797
Immediate Actions Required
- Update the User Access Manager plugin to the patched version released after 2.3.18 on all WordPress sites.
- Invalidate active administrator sessions and require re-authentication after upgrading.
- Review recent admin activity, user roles, and installed plugins for unauthorized changes.
Patch Information
The vulnerability was addressed in the plugin repository via changeset 3680890. Administrators should upgrade to the next release above 2.3.18 and verify the version in the WordPress plugins dashboard.
Workarounds
- Deactivate and remove the User Access Manager plugin until the patched version can be installed.
- Restrict access to /wp-admin/ by IP allowlist using web server or reverse proxy rules.
- Add a WAF rule that blocks requests where tab_group_section contains HTML metacharacters such as <, >, ", or ' in encoded or literal form.
- Enforce administrator use of browsers with strict script isolation and require multi-factor authentication for all privileged accounts.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.