CVE-2022-21664 Overview
CVE-2022-21664 is a SQL Injection vulnerability affecting WordPress, the widely-used open-source content management system written in PHP and paired with a MariaDB database. Due to lack of proper sanitization in the WP_Meta_Query and WP_Tax_Query classes, there is potential for unintended SQL queries to be executed. This vulnerability allows authenticated attackers with low privileges to manipulate database queries, potentially leading to unauthorized data access, data modification, or complete database compromise.
Critical Impact
Authenticated attackers can exploit improper alias sanitization in WordPress query classes to execute arbitrary SQL queries, potentially compromising the entire WordPress database including user credentials and sensitive content.
Affected Products
- WordPress versions prior to 5.8.3 (with security patches backported to version 4.1.34)
- Debian Linux 9.0, 10.0, and 11.0
- Fedora 34 and 35
Discovery Timeline
- January 6, 2022 - CVE-2022-21664 published to NVD
- November 21, 2024 - Last updated in NVD database
Technical Details for CVE-2022-21664
Vulnerability Analysis
This SQL Injection vulnerability (CWE-89) stems from insufficient input validation in WordPress's query handling classes. The vulnerability exists within the WP_Meta_Query class (class-wp-meta-query.php) and the WP_Tax_Query class (class-wp-tax-query.php), where sibling alias values are used directly in SQL query construction without proper sanitization.
The attack requires network access and low-privilege authentication, but once these conditions are met, the exploitation complexity is low. A successful attack can result in complete compromise of confidentiality, integrity, and availability of the WordPress database.
Root Cause
The root cause of CVE-2022-21664 lies in the improper handling of the alias property when building SQL queries. In both WP_Meta_Query and WP_Tax_Query, when comparing clauses with compatible operators, the sibling's alias value was directly assigned without sanitization. This allowed non-word characters to be passed through, enabling SQL injection attacks.
The vulnerable code directly assigned $sibling['alias'] to $alias without filtering potentially malicious characters that could break out of the intended SQL context.
Attack Vector
The attack vector is network-based and requires an authenticated user with low privileges. An attacker could craft malicious input that includes SQL injection payloads through the alias parameter. When WordPress processes meta or taxonomy queries, the unsanitized alias value could be incorporated into the final SQL statement, allowing the attacker to:
- Extract sensitive data from the database
- Modify or delete database records
- Potentially escalate privileges by manipulating user tables
- Compromise the entire WordPress installation
// Security patch in src/wp-includes/class-wp-meta-query.php
// Before: Unsanitized alias assignment
// $alias = $sibling['alias'];
// After: Sanitized alias using regex to remove non-word characters
$clause_compare = strtoupper( $clause['compare'] );
$sibling_compare = strtoupper( $sibling['compare'] );
if ( in_array( $clause_compare, $compatible_compares, true ) && in_array( $sibling_compare, $compatible_compares, true ) ) {
- $alias = $sibling['alias'];
+ $alias = preg_replace( '/\W/', '_', $sibling['alias'] );
break;
}
}
Source: GitHub Commit Change
// Security patch in src/wp-includes/class-wp-tax-query.php
// Same sanitization pattern applied to taxonomy queries
// The sibling must both have compatible operator to share its alias.
if ( in_array( strtoupper( $sibling['operator'] ), $compatible_operators, true ) ) {
- $alias = $sibling['alias'];
+ $alias = preg_replace( '/\W/', '_', $sibling['alias'] );
break;
}
}
Source: GitHub Commit Change
Detection Methods for CVE-2022-21664
Indicators of Compromise
- Unusual database queries in MySQL/MariaDB slow query logs or general query logs containing unexpected SQL syntax
- Error logs showing SQL syntax errors or database connection anomalies
- Unexpected data modifications in wp_postmeta, wp_termmeta, or taxonomy tables
- Authentication logs showing suspicious activity from low-privilege accounts followed by elevated data access
Detection Strategies
- Monitor web application firewall (WAF) logs for SQL injection patterns targeting WordPress meta and taxonomy query endpoints
- Implement database activity monitoring to detect anomalous query patterns or unauthorized data access
- Review WordPress debug logs for unexpected query construction errors
- Deploy intrusion detection signatures that identify SQL injection attempts in WordPress-specific parameters
Monitoring Recommendations
- Enable MySQL/MariaDB general query logging temporarily to audit query patterns during incident investigation
- Configure alerts for failed or unusual database queries originating from the WordPress application
- Monitor file integrity of core WordPress files, particularly class-wp-meta-query.php and class-wp-tax-query.php
- Track user activity logs for authenticated users performing unusual meta or taxonomy operations
How to Mitigate CVE-2022-21664
Immediate Actions Required
- Update WordPress to version 5.8.3 or later immediately using the WordPress admin dashboard or WP-CLI
- For older installations, apply the security releases available back to version 4.1.34
- Enable WordPress auto-updates to ensure timely application of future security patches
- Review database logs for any signs of prior exploitation attempts
Patch Information
WordPress has addressed this vulnerability in version 5.8.3, released as part of a security release on January 6, 2022. The fix applies regex sanitization using preg_replace('/\W/', '_', $sibling['alias']) to replace all non-word characters with underscores, effectively neutralizing SQL injection payloads. Security patches have been backported to all supported WordPress versions going back to 4.1.34.
For additional details, refer to the WordPress Security Release and the GitHub Security Advisory.
Debian users should apply updates per the Debian Security Advisory DSA-5039. Fedora users should update via the official Fedora package announcements.
Workarounds
- There are no known workarounds for this vulnerability; updating WordPress is the only effective mitigation
- As a temporary defense-in-depth measure, implement a web application firewall (WAF) with SQL injection detection rules
- Consider restricting user registration and reducing the number of authenticated users until patches are applied
- Enable WordPress maintenance mode to limit exposure while applying updates
# Update WordPress via WP-CLI
wp core update
# Verify WordPress version after update
wp core version
# Enable auto-updates for future security releases
wp config set WP_AUTO_UPDATE_CORE true --raw
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
