CVE-2026-57648 Overview
CVE-2026-57648 is a broken access control vulnerability in the Nelio Content plugin for WordPress, affecting versions up to and including 4.3.4. The flaw is classified under CWE-862: Missing Authorization and allows authenticated users with Contributor-level privileges to perform actions that should be restricted to higher-privileged roles. Exploitation requires a valid low-privilege account on the target WordPress site. The vulnerability affects the integrity of plugin-managed data without requiring user interaction.
Critical Impact
Authenticated contributors can bypass authorization checks in Nelio Content to modify plugin-controlled resources, resulting in unauthorized changes to content workflows on affected WordPress sites.
Affected Products
- Nelio Content WordPress plugin, versions <= 4.3.4
- WordPress sites with contributor-level user registration enabled
- Multi-author WordPress environments running vulnerable plugin releases
Discovery Timeline
- 2026-06-26 - CVE-2026-57648 published to the National Vulnerability Database (NVD)
- 2026-06-29 - Last updated in NVD database
Technical Details for CVE-2026-57648
Vulnerability Analysis
CVE-2026-57648 is a broken access control weakness in the Nelio Content plugin for WordPress. The plugin exposes functionality intended for editors and administrators without enforcing sufficient capability checks. An attacker with Contributor role access can invoke these actions and manipulate plugin-managed state.
The vulnerability maps to CWE-862 (Missing Authorization). Missing authorization flaws occur when server-side code executes privileged operations without validating whether the caller holds the required capability. In WordPress plugins this typically means omitting current_user_can() checks or relying only on nonce verification.
The integrity impact is limited to plugin-controlled data rather than the underlying WordPress core. Confidentiality and availability are not affected according to the published vector. The Exploit Prediction Scoring System places this issue at a low likelihood of near-term exploitation.
Root Cause
The root cause is the absence of a capability check on one or more request handlers in Nelio Content up to version 4.3.4. The plugin trusts that the authenticated session belongs to a sufficiently privileged user rather than verifying the specific capability required for the requested action.
Attack Vector
An attacker first obtains Contributor-level credentials on the target WordPress site through legitimate registration, credential compromise, or social engineering. The attacker then sends authenticated HTTP requests to the vulnerable plugin endpoint. Because the endpoint does not verify authorization, the request executes with the plugin's intended privilege level rather than the caller's. The vulnerability mechanism is documented in the Patchstack Vulnerability Report.
Detection Methods for CVE-2026-57648
Indicators of Compromise
- Unexpected modifications to Nelio Content editorial calendars, tasks, or scheduled posts performed by Contributor accounts
- WordPress access logs showing Contributor users issuing POST or AJAX requests to Nelio Content administrative endpoints
- New or modified plugin-managed records lacking a corresponding editor or administrator audit trail
Detection Strategies
- Audit the WordPress wp_users and wp_usermeta tables for recently created Contributor accounts, particularly on sites with open registration
- Correlate web server access logs with WordPress user roles to identify low-privilege users invoking privileged plugin routes
- Review Nelio Content activity history against WordPress role assignments for actions that exceed the actor's documented capabilities
Monitoring Recommendations
- Enable WordPress audit logging plugins to capture role-based action attribution for all plugin endpoints
- Alert on HTTP requests to Nelio Content REST or admin-ajax handlers originating from non-editor session cookies
- Track version metadata of installed plugins and flag any WordPress instance still running Nelio Content <= 4.3.4
How to Mitigate CVE-2026-57648
Immediate Actions Required
- Update Nelio Content to a release later than 4.3.4 as soon as the vendor publishes a fixed version
- Inventory all WordPress deployments to identify installations running the vulnerable plugin range
- Review and reduce Contributor account membership, removing accounts that are inactive or unnecessary
Patch Information
Refer to the Patchstack Vulnerability Report for the authoritative fixed version and vendor advisory details. Apply the vendor patch through the WordPress plugin updater or by replacing the plugin directory with the fixed release.
Workarounds
- Disable the Nelio Content plugin on sites where an immediate upgrade is not feasible
- Restrict Contributor role registration by disabling open user registration in WordPress general settings
- Deploy a web application firewall rule that blocks Contributor-session requests to Nelio Content administrative endpoints until the plugin is patched
# Configuration example: disable open registration and audit contributor accounts
wp option update users_can_register 0
wp user list --role=contributor --fields=ID,user_login,user_registered,user_email
wp plugin deactivate nelio-content
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
