CVE-2025-30523: Super Simple Subscriptions SQLi Flaw

CVE-2025-30523 Overview

CVE-2025-30523 is a SQL injection vulnerability affecting the Marcel-NL Super Simple Subscriptions WordPress plugin. The flaw exists in super-simple-subscriptions versions up to and including 1.1.0. An authenticated attacker with high privileges can inject malicious SQL into database queries through improperly neutralized input. The vulnerability is classified under CWE-89 (Improper Neutralization of Special Elements used in an SQL Command). Successful exploitation can disclose sensitive database contents and degrade application availability. The scope is marked as changed, meaning the impact extends beyond the vulnerable component.

Critical Impact
Authenticated attackers can extract confidential data from the WordPress database and disrupt subscription functionality through crafted SQL payloads.

Affected Products

Marcel-NL Super Simple Subscriptions plugin for WordPress
All versions from initial release through 1.1.0
WordPress sites with the super-simple-subscriptions plugin installed and active

Discovery Timeline

2025-03-24 - CVE-2025-30523 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-30523

Vulnerability Analysis

The vulnerability stems from improper neutralization of special characters in SQL statements within the Super Simple Subscriptions plugin. User-supplied input reaches database query construction without adequate sanitization or parameterization. Attackers with high-privilege authentication can craft input containing SQL metacharacters to alter the intended query logic. The plugin processes these inputs as part of dynamic SQL strings rather than bound parameters. As a result, injected SQL executes within the WordPress database context. The Exploit Prediction Scoring System (EPSS) places this issue at the 37th percentile, indicating modest near-term exploitation probability. The scope change in the CVSS vector reflects impact on resources beyond the plugin itself, including the underlying WordPress database.

Root Cause

The root cause is the absence of prepared statements or proper escaping when handling user input passed to SQL queries. WordPress provides $wpdb->prepare() for parameterized queries, but the plugin code paths handling subscription-related operations do not consistently apply this protection. CWE-89 captures this class of weakness, where untrusted data flows directly into a query string.

Attack Vector

Exploitation requires network access and authenticated session credentials with high privileges on the target WordPress site. The attacker submits HTTP requests containing SQL injection payloads to plugin endpoints that interact with the database. No user interaction is required beyond the attacker's own session. The vulnerability mechanism is documented in the Patchstack SQL Injection Vulnerability advisory. No public proof-of-concept code has been released at this time.

Detection Methods for CVE-2025-30523

Indicators of Compromise

Unexpected SQL syntax characters such as UNION, SELECT, --, or ' within HTTP request parameters targeting super-simple-subscriptions endpoints
Anomalous database query patterns in MySQL slow query or general logs originating from the plugin
Unusual administrative or privileged user activity correlating with subscription plugin requests

Detection Strategies

Deploy a web application firewall (WAF) with rulesets that flag SQL injection patterns in requests to /wp-admin/admin.php and plugin AJAX handlers
Enable WordPress query monitoring plugins or database audit logging to identify malformed or unexpected SQL statements
Review authentication logs for high-privilege account activity preceding suspicious database queries

Monitoring Recommendations

Forward WordPress, web server, and database logs to a centralized log analytics platform for correlation
Alert on outbound data transfers from web servers that exceed normal baselines following plugin requests
Monitor file integrity for the super-simple-subscriptions plugin directory to detect tampering

How to Mitigate CVE-2025-30523

Immediate Actions Required

Audit all WordPress installations for the presence of the super-simple-subscriptions plugin at version 1.1.0 or earlier
Deactivate and remove the plugin until a patched release is verified and deployed
Rotate credentials for any high-privilege WordPress accounts that may have been exposed
Review database contents for unauthorized modifications or data exfiltration evidence

Patch Information

At the time of NVD publication, no fixed version is identified beyond 1.1.0. Administrators should consult the Patchstack advisory for current patch availability and apply vendor updates as soon as they are released.

Workarounds

Restrict access to WordPress administrative endpoints using IP allowlisting or VPN-only access
Apply WAF virtual patching rules that block SQL injection signatures targeting the plugin's endpoints
Reduce the number of accounts with high-privilege WordPress roles to minimize the attack surface
Enforce strong authentication, including multi-factor authentication, on all administrative accounts

bash

# Example WAF rule snippet to block common SQLi patterns on plugin endpoints
SecRule REQUEST_URI "@contains super-simple-subscriptions" \
  "phase:2,deny,status:403,id:1003052,\
   chain,msg:'Block SQLi attempts against Super Simple Subscriptions'"
SecRule ARGS "@rx (?i)(union(.*?)select|--|';|/\*)" "t:none"