CVE-2026-1258: Mail Mint WordPress Plugin SQL Injection

CVE-2026-1258 Overview

The Mail Mint plugin for WordPress contains a blind SQL Injection vulnerability affecting multiple API endpoints including forms, automation, email/templates, and contacts/import/tutorlms/map. The vulnerability exists in all versions up to and including 1.19.2 due to insufficient escaping of user-supplied parameters and inadequate preparation of SQL queries. This security flaw allows authenticated attackers with administrator-level access to append additional SQL queries to existing database operations, potentially leading to unauthorized data extraction.

Critical Impact

Authenticated attackers with administrator privileges can exploit blind SQL injection to extract sensitive database contents including user credentials, email lists, and confidential business data stored within WordPress.

Affected Products

• Mail Mint plugin for WordPress versions up to and including 1.19.2
• WordPress installations running vulnerable Mail Mint versions
• Sites utilizing Mail Mint's forms, automation, email templates, or TutorLMS contact import features

Discovery Timeline

• 2026-02-14 - CVE CVE-2026-1258 published to NVD
• 2026-02-18 - Last updated in NVD database

Technical Details for CVE-2026-1258

Vulnerability Analysis

This SQL Injection vulnerability (CWE-89) stems from improper neutralization of special elements used in SQL commands. The Mail Mint plugin fails to properly sanitize and escape user-controlled input before incorporating it into database queries. Specifically, the vulnerable parameters order-by, order-type, and selectedCourses are passed directly into SQL statements without adequate validation or parameterized query implementation.

The blind nature of this injection means attackers cannot directly observe query results in the application response. Instead, they must infer database information through observable differences in application behavior, timing-based techniques, or out-of-band data exfiltration methods. While this requires administrator-level access, compromised admin accounts or insider threats could leverage this vulnerability to extract sensitive data from the WordPress database.

Root Cause

The root cause is insufficient input validation and lack of prepared statements in the affected API endpoints. The plugin directly concatenates user-supplied values for the order-by, order-type, and selectedCourses parameters into SQL query strings rather than using WordPress's built-in $wpdb->prepare() function for parameterized queries. This architectural flaw allows malicious SQL syntax to be interpreted as part of the query structure rather than as literal data values.

Attack Vector

The attack is conducted over the network against the WordPress REST API endpoints exposed by Mail Mint. An attacker must first authenticate to WordPress with administrator-level privileges. Once authenticated, they can craft malicious requests to the vulnerable endpoints containing SQL injection payloads in the order-by, order-type, or selectedCourses parameters. The blind SQL injection technique typically involves:

1. Sending requests with conditional SQL statements that alter application behavior based on true/false conditions
2. Using time-based payloads (e.g., SLEEP() functions) to infer data through response timing differences
3. Systematically extracting database contents character by character through boolean-based inference

The vulnerability affects multiple files within the plugin architecture, including TemplateAction.php, FormModel.php, AutomationStore.php, and Import.php, indicating a systemic pattern of insecure SQL query construction.

Detection Methods for CVE-2026-1258

Indicators of Compromise

• Unusual SQL-related error messages in WordPress debug logs referencing Mail Mint API endpoints
• HTTP requests to Mail Mint API endpoints containing SQL syntax characters (', ", ;, --, UNION, SELECT) in order-by, order-type, or selectedCourses parameters
• Abnormally slow response times from Mail Mint admin API calls indicating time-based SQL injection attempts
• Unexpected database queries in MySQL slow query logs originating from Mail Mint plugin tables

Detection Strategies

• Implement web application firewall (WAF) rules to detect SQL injection patterns in requests to /wp-json/mail-mint/ API routes
• Monitor WordPress admin API access logs for requests containing suspicious parameter values with SQL keywords
• Deploy real-time database activity monitoring to identify anomalous query patterns against Mail Mint tables
• Configure SentinelOne Singularity to alert on process behaviors consistent with SQL injection exploitation

Monitoring Recommendations

• Enable verbose logging for the Mail Mint plugin and regularly review logs for injection attempt patterns
• Set up alerting for high-frequency requests to vulnerable Mail Mint endpoints from single administrator sessions
• Monitor database server metrics for unusual CPU or I/O spikes that may indicate time-based blind SQL injection attacks
• Implement baseline profiling of normal Mail Mint API usage to detect statistical anomalies

How to Mitigate CVE-2026-1258

Immediate Actions Required

• Update the Mail Mint plugin to the latest patched version beyond 1.19.2 immediately
• Audit WordPress administrator accounts to ensure no unauthorized admin-level users exist
• Review database access logs for any evidence of exploitation prior to patching
• Implement web application firewall rules to block SQL injection patterns as a defense-in-depth measure

Patch Information

Security patches addressing this vulnerability have been released by the Mail Mint development team. The fixes are documented in the WordPress Mail Mint changeset 3449536, which includes modifications to multiple affected files including TemplateAction.php, FormModel.php, AutomationStore.php, and Import.php. Site administrators should update to the latest available version through the WordPress plugin repository. Additional vulnerability details are available in the Wordfence Threat Intelligence advisory.

Workarounds

• Restrict access to WordPress administrator accounts using strong authentication and IP allowlisting until patching is complete
• Disable the Mail Mint plugin temporarily if the vulnerable functionality is not critical to operations
• Implement WAF rules specifically blocking requests with SQL injection patterns to the affected API endpoints
• Enable WordPress audit logging to monitor for any suspicious administrator activity targeting Mail Mint endpoints

# Example: Block suspicious requests via .htaccess (temporary mitigation)
# Add to WordPress root .htaccess file
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{QUERY_STRING} (order-by|order-type|selectedCourses)=.*(\%27|\'|\%22|\"|;|\%3B) [NC]
RewriteCond %{REQUEST_URI} mail-mint [NC]
RewriteRule .* - [F,L]
</IfModule>