CVE-2025-39595: Quentn WP SQL Injection Vulnerability

CVE-2025-39595 Overview

CVE-2025-39595 is a critical SQL Injection vulnerability affecting the Quentn WP WordPress plugin developed by Quentn.com GmbH. The vulnerability stems from improper neutralization of special elements used in SQL commands (CWE-89), allowing attackers to manipulate database queries through maliciously crafted input. This flaw enables unauthenticated remote attackers to extract sensitive data from the WordPress database, potentially compromising the entire site and its users.

Critical Impact

Unauthenticated attackers can exploit this SQL Injection vulnerability to extract sensitive database contents including user credentials, email addresses, and other confidential information stored in the WordPress database.

Affected Products

• Quentn WP plugin versions from n/a through 1.2.8
• WordPress installations using the vulnerable Quentn WP plugin
• Marketing automation integrations dependent on Quentn WP functionality

Discovery Timeline

• April 17, 2025 - CVE-2025-39595 published to NVD
• April 17, 2025 - Last updated in NVD database

Technical Details for CVE-2025-39595

Vulnerability Analysis

This SQL Injection vulnerability in the Quentn WP plugin allows attackers to inject malicious SQL statements into application queries. The vulnerability is network-accessible and requires no authentication or user interaction to exploit, making it particularly dangerous for exposed WordPress installations. The scope of the vulnerability extends beyond the vulnerable component itself, potentially allowing attackers to access data across the entire WordPress database. While the primary impact is high confidentiality breach through data exfiltration, the vulnerability also presents a low availability impact, potentially enabling denial-of-service conditions through resource-intensive queries.

Root Cause

The root cause of CVE-2025-39595 is the failure to properly sanitize and validate user-supplied input before incorporating it into SQL queries. The Quentn WP plugin does not adequately implement prepared statements or parameterized queries, allowing special SQL characters and commands to be interpreted as executable code rather than data. This lack of input neutralization enables attackers to escape intended query contexts and inject arbitrary SQL commands.

Attack Vector

The attack vector for this vulnerability is network-based, requiring no authentication or privileges. Attackers can craft malicious HTTP requests containing SQL injection payloads targeting vulnerable plugin endpoints. Since WordPress sites are typically internet-facing, this dramatically increases the exposure surface. The attack complexity is low, and no user interaction is required, meaning automated exploitation tools could potentially scan and exploit vulnerable installations at scale.

The vulnerability can be exploited through various SQL injection techniques including UNION-based injection for data extraction, blind SQL injection for inferring database contents, and time-based techniques for environments where direct output is not available. For detailed technical analysis, refer to the Patchstack security advisory.

Detection Methods for CVE-2025-39595

Indicators of Compromise

• Unusual database query patterns or errors in WordPress error logs related to the Quentn WP plugin
• Unexpected database connections or queries with anomalous execution times
• Evidence of data exfiltration attempts in web server access logs, particularly requests with SQL syntax characters
• WordPress database access from unfamiliar IP addresses or at unusual times

Detection Strategies

• Monitor web application firewall (WAF) logs for SQL injection attack signatures targeting WordPress plugin endpoints
• Implement database activity monitoring to detect unusual query patterns or unauthorized data access
• Review access logs for requests containing SQL metacharacters such as single quotes, double dashes, or UNION keywords
• Deploy intrusion detection rules specifically targeting WordPress plugin exploitation attempts

Monitoring Recommendations

• Enable verbose logging for the Quentn WP plugin and related database interactions
• Configure real-time alerting for failed SQL queries or database errors originating from web requests
• Establish baseline database query patterns to identify anomalous activity
• Monitor for bulk data extraction indicators such as unusual outbound data transfers

How to Mitigate CVE-2025-39595

Immediate Actions Required

• Audit current WordPress installations to identify any instances of the Quentn WP plugin at version 1.2.8 or earlier
• Temporarily deactivate the Quentn WP plugin if it cannot be immediately updated
• Implement web application firewall rules to block common SQL injection attack patterns
• Review database access logs for evidence of prior exploitation attempts

Patch Information

Organizations should immediately check for updated versions of the Quentn WP plugin beyond version 1.2.8 that address this SQL Injection vulnerability. Monitor the official WordPress plugin repository and the Patchstack security advisory for patch availability and update instructions. Until a patch is available, implement the workarounds described below.

Workarounds

• Disable the Quentn WP plugin entirely until a patched version is released
• Implement strict web application firewall rules to filter SQL injection payloads in requests to WordPress
• Restrict database user privileges for the WordPress installation to minimize potential damage from successful exploitation
• Consider implementing additional input validation at the server level through .htaccess rules or reverse proxy configurations

# Example WAF rule configuration for ModSecurity
# Add to WordPress .htaccess or ModSecurity configuration
SecRule REQUEST_URI "@contains quentn" \
  "id:100001,phase:2,deny,status:403,\
  chain"
SecRule ARGS "@detectSQLi" \
  "t:none,t:urlDecodeUni,t:htmlEntityDecode,\
  msg:'SQL Injection attempt blocked for Quentn WP'"