CVE-2026-6453: CubeWP Framework Plugin SQLi Vulnerability

CVE-2026-6453 Overview

CVE-2026-6453 is an authenticated SQL injection vulnerability in the CubeWP Framework plugin for WordPress. The flaw affects all plugin versions up to and including 1.1.30. The issue resides in the cubewp_remove_relation() AJAX handler, which interpolates the relation_id parameter directly into a raw SQL query. Authenticated attackers with subscriber-level access can append arbitrary SQL to the existing query and extract sensitive data from the WordPress database. The vulnerability is classified under CWE-89 (Improper Neutralization of Special Elements used in an SQL Command).

Critical Impact
Authenticated users with subscriber privileges can execute injected SQL against the WordPress database, exposing user credentials, session tokens, and other confidential records.

Affected Products

CubeWP Framework plugin for WordPress, all versions through 1.1.30
WordPress sites permitting subscriber-level registration with the plugin active
Any WordPress deployment exposing the vulnerable cubewp_remove_relation AJAX endpoint

Discovery Timeline

2026-08-01 - CVE-2026-6453 published to NVD
2026-08-03 - Last updated in NVD database

Technical Details for CVE-2026-6453

Vulnerability Analysis

The vulnerability exists in the cubewp_remove_relation() AJAX function within the CubeWP Framework plugin. The handler receives the relation_id parameter from a POST request and processes it through wp_unslash() before passing it to sanitize_text_field(). The value is then interpolated directly into a raw SQL string executed by $wpdb without using the $wpdb->prepare() parameterized query API. Because $wpdb->prepare() is bypassed, attacker-supplied SQL fragments become part of the executed statement. Injected UNION SELECT clauses can return arbitrary column data from tables such as wp_users or wp_usermeta.

Root Cause

The root cause is the deliberate removal of WordPress's default input escaping followed by unsafe string interpolation. WordPress applies wp_magic_quotes() to all $_POST data, which prepends backslashes to quotes and other metacharacters. The wp_unslash() call in cubewp_remove_relation() strips this protection. The subsequent sanitize_text_field() call trims whitespace and removes tags but performs no SQL-context escaping. The resulting string is placed directly into a SQL query, allowing metacharacters to break out of the intended value context.

Attack Vector

An authenticated user with subscriber privileges or higher sends a crafted POST request to the WordPress AJAX endpoint targeting the cubewp_remove_relation action. The relation_id parameter carries the SQL injection payload. Because the endpoint accepts any authenticated role, subscriber-level accounts obtained through open registration are sufficient. The attack requires network access to the WordPress admin AJAX handler and no user interaction beyond the attacker's own session.

No verified public exploit code is available. Technical details of the vulnerable code paths are documented in the Wordfence Vulnerability Report and in the plugin source at the CubeWP admin functions file and the relationships class.

Detection Methods for CVE-2026-6453

Indicators of Compromise

POST requests to /wp-admin/admin-ajax.php with action=cubewp_remove_relation containing SQL metacharacters such as single quotes, UNION, SELECT, or SLEEP in the relation_id parameter
Unusually long or URL-encoded relation_id values submitted by low-privilege accounts
Spikes in AJAX traffic from newly registered subscriber accounts
New administrator accounts or modified wp_users records following suspicious AJAX activity

Detection Strategies

Enable WordPress database query logging and inspect statements generated by the cubewp_remove_relation action for anomalous syntax
Deploy a web application firewall (WAF) rule that inspects the relation_id POST parameter for SQL keywords and metacharacters
Correlate authentication events for subscriber accounts with subsequent AJAX requests to the vulnerable endpoint
Alert on responses to admin-ajax.php that return abnormally large payloads consistent with data exfiltration

Monitoring Recommendations

Forward WordPress access logs and PHP error logs to a centralized SIEM for retention and analytics
Track the plugin version across managed WordPress instances and flag any host still running CubeWP Framework <= 1.1.30
Monitor outbound connections from the web server for indicators of secondary tooling or data staging

How to Mitigate CVE-2026-6453

Immediate Actions Required

Update the CubeWP Framework plugin to the version released after 1.1.30 that removes the vulnerable code path
Audit WordPress user tables for unauthorized administrator accounts and rotate credentials if compromise is suspected
Disable open subscriber registration on sites that do not require it to reduce the pool of authenticated attackers
Restrict access to /wp-admin/admin-ajax.php where feasible using IP allowlists or authentication proxies

Patch Information

The vendor has committed a fix in the plugin repository. The corrective change is recorded in the WordPress plugin changeset. Administrators should upgrade to the first plugin release that includes this changeset. Details of the fixed version and remediation guidance are available in the Wordfence advisory.

Workarounds

Deactivate the CubeWP Framework plugin until the patched version is installed
Deploy a WAF rule blocking POST requests to admin-ajax.php where action=cubewp_remove_relation and relation_id contains SQL metacharacters
Remove the cubewp_remove_relation AJAX action registration through a custom must-use plugin if immediate upgrade is not possible
Enforce the principle of least privilege by revoking subscriber accounts that are not required for site functionality

bash

# Example ModSecurity rule blocking SQL metacharacters in the vulnerable parameter
SecRule REQUEST_URI "@contains /wp-admin/admin-ajax.php" \
    "chain,phase:2,deny,status:403,id:1026453,\
    msg:'CVE-2026-6453 CubeWP SQLi attempt'"
  SecRule ARGS:action "@streq cubewp_remove_relation" \
    "chain"
    SecRule ARGS:relation_id "@rx (?i)(union|select|sleep|--|/\*|')" "t:none,t:urlDecodeUni"