CVE-2026-10033: EventON Action User Auth Bypass Flaw

CVE-2026-10033 Overview

CVE-2026-10033 is an authorization bypass vulnerability in the EventON Action User plugin for WordPress. The flaw affects all versions up to and including 2.5.14. The plugin fails to verify whether the caller is authorized to invoke sensitive AJAX actions. Unauthenticated attackers can grant EventON management capabilities and the upload_files capability to any non-administrator role or user, escalating privileges on the target site. The same exposure enables enumeration of WordPress users with their IDs and display names, disclosure of role and capability state along with nonce values, and tampering with event-to-user term assignments. The issue is tracked under [CWE-862] Missing Authorization.

Critical Impact
Unauthenticated attackers can escalate privileges of arbitrary non-administrator WordPress accounts and exfiltrate user, role, and nonce data from vulnerable sites.

Affected Products

EventON Action User plugin for WordPress
All versions up to and including 2.5.14
WordPress sites with the vulnerable plugin activated

Discovery Timeline

2026-07-24 - CVE-2026-10033 published to the National Vulnerability Database (NVD)
2026-07-24 - Last updated in NVD database

Technical Details for CVE-2026-10033

Vulnerability Analysis

The EventON Action User plugin exposes AJAX handlers that do not verify the caller's authorization before executing privileged operations. Because the endpoints are reachable without authentication, any remote attacker who can reach the WordPress site can invoke them. The most impactful handler updates role capabilities and assigns the upload_files capability along with EventON management capabilities. Attackers can select any WordPress role other than administrator, or any individual non-administrator user, and elevate that principal's permissions.

Additional handlers leak information useful for follow-on attacks. Attackers can enumerate all WordPress users along with their IDs and display names, retrieve role and capability state, and read valid nonce values. Exposed nonces enable subsequent operations that would normally require an authenticated session. Attackers can also tamper with event-to-user term assignments, corrupting event ownership metadata.

Root Cause

The root cause is missing authorization ([CWE-862]) inside AJAX action handlers registered by the plugin. According to the WordPress Plugin Code Review, the affected handlers do not gate execution behind a current_user_can() capability check or a valid nonce verification tied to an authenticated session. An early-return guard inside update_role_caps() protects the administrator role, so administrator-level accounts cannot be modified through the same path. All other roles and individual non-administrator users remain reachable.

Attack Vector

The attack vector is network-based and requires no authentication or user interaction. An attacker sends crafted HTTP POST requests to the WordPress admin-ajax.php endpoint targeting the vulnerable plugin actions. The attacker first calls the enumeration handler to list users and roles, then invokes the role-capability update handler to grant upload_files and EventON management capabilities to a chosen non-administrator role. Once a lower-privilege account can upload files, further post-exploitation such as web shell staging becomes feasible depending on site configuration.

No verified public exploit code is available at this time. Refer to the Wordfence Vulnerability Report for additional technical detail.

Detection Methods for CVE-2026-10033

Indicators of Compromise

Unexpected assignment of the upload_files capability to non-administrator WordPress roles such as subscriber, contributor, or author.
WordPress role definitions containing EventON management capabilities on roles that should not possess them.
New or modified uploads under wp-content/uploads/ originating from low-privilege accounts.
Anomalous event-to-user term assignments in the wp_term_relationships table tied to EventON custom taxonomies.

Detection Strategies

Monitor POST requests to wp-admin/admin-ajax.php referencing EventON Action User plugin actions from unauthenticated sessions.
Audit the wp_options table entries that store role capabilities (for example, wp_user_roles) for unexpected additions.
Alert on rapid, sequential AJAX calls that enumerate users followed by capability-modification requests from the same source IP.

Monitoring Recommendations

Enable WordPress audit logging for role and capability changes with immediate alerting on privilege additions.
Ingest web server access logs into a centralized analytics platform and pivot on admin-ajax.php traffic patterns.
Track file upload events from non-administrator accounts, particularly executable extensions or PHP handlers.

How to Mitigate CVE-2026-10033

Immediate Actions Required

Update the EventON Action User plugin to a version later than 2.5.14 as soon as a fixed release is available from the vendor.
If no patched version is available, deactivate and remove the plugin from all WordPress installations.
Audit all non-administrator roles and user accounts for unauthorized upload_files or EventON management capabilities and revoke any unexpected grants.
Rotate WordPress secret keys and salts in wp-config.php to invalidate any leaked nonce values.

Patch Information

At the time of publication, the NVD entry for CVE-2026-10033 does not list a fixed version. Site operators should monitor the Wordfence Vulnerability Report and the plugin's WordPress.org listing for a patched release. Apply the vendor patch immediately once available.

Workarounds

Block unauthenticated POST requests to admin-ajax.php targeting EventON Action User actions using a web application firewall (WAF) rule.
Restrict access to admin-ajax.php from untrusted networks where feasible, permitting only authenticated sessions.
Temporarily remove the upload_files capability from all non-administrator roles until the plugin is patched or removed.

bash

# Configuration example: WP-CLI audit and remediation
wp role list --fields=role,capabilities
wp cap remove subscriber upload_files
wp cap remove contributor upload_files
wp plugin deactivate eventon-action-user
wp plugin delete eventon-action-user