CVE-2025-11833: Post SMTP Information Disclosure Flaw

CVE-2025-11833 Overview

CVE-2025-11833 is a critical authorization bypass vulnerability in the Post SMTP – Complete SMTP Solution with Logs, Alerts, Backup SMTP & Mobile App plugin for WordPress. The vulnerability exists due to a missing capability check on the __construct function in all versions up to and including 3.6.0. This security flaw allows unauthenticated attackers to read arbitrary logged emails sent through the Post SMTP plugin, including password reset emails containing sensitive password reset links, which can lead to complete account takeover.

Critical Impact

Unauthenticated attackers can access logged emails including password reset links, enabling full WordPress account takeover without any authentication.

Affected Products

• Post SMTP – Complete SMTP Solution with Logs, Alerts, Backup SMTP & Mobile App plugin for WordPress versions up to and including 3.6.0

Discovery Timeline

• 2025-11-01 - CVE CVE-2025-11833 published to NVD
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2025-11833

Vulnerability Analysis

This vulnerability is classified under CWE-862 (Missing Authorization), representing a fundamental failure in access control implementation. The __construct function in the PostmanEmailLogs.php file fails to verify that the requesting user has appropriate permissions before processing requests related to email log access.

When WordPress sites use the Post SMTP plugin to handle email delivery, the plugin maintains logs of sent emails for debugging and auditing purposes. These logs contain the full content of emails, including sensitive information such as password reset links, account verification tokens, and other confidential communications. Without proper authorization checks, any unauthenticated user can query these email logs and retrieve their contents.

The impact of this vulnerability is particularly severe because password reset emails typically contain one-time use tokens that grant direct access to user accounts. An attacker exploiting this flaw could intercept password reset links for administrator accounts, effectively gaining complete control over the WordPress installation.

Root Cause

The root cause of this vulnerability lies in the missing capability check within the __construct function of the PostmanEmailLogs.php file. WordPress provides a robust capability system that allows developers to restrict access to sensitive functionality based on user roles and permissions. However, the vulnerable code fails to invoke functions like current_user_can() to verify that the requesting user has administrative privileges before serving email log data.

The vulnerable code path allows direct access to the email log retrieval functionality without any authentication or authorization validation, exposing all logged email content to unauthenticated users.

Attack Vector

The attack can be executed remotely over the network without requiring any authentication or user interaction. An attacker can directly access the vulnerable endpoint to retrieve logged emails. The exploitation process involves:

1. Identifying WordPress sites using the vulnerable Post SMTP plugin
2. Sending crafted requests to access the email log functionality
3. Retrieving logged emails including password reset messages
4. Extracting password reset links or other sensitive tokens from the email content
5. Using the extracted tokens to take over WordPress user accounts, including administrators

The vulnerability is particularly dangerous because the attacker requires no prior authentication, making mass exploitation feasible against any WordPress site running the vulnerable plugin version.

Detection Methods for CVE-2025-11833

Indicators of Compromise

• Unexpected access to WordPress AJAX endpoints related to Post SMTP email log retrieval from unauthenticated sources
• Anomalous HTTP requests targeting /wp-admin/admin-ajax.php with Post SMTP related actions from external IP addresses
• Multiple password reset requests followed by successful logins from different IP addresses
• Evidence of email log access in web server logs from unauthenticated sessions

Detection Strategies

• Monitor web server access logs for requests to Post SMTP related endpoints from unauthenticated users
• Implement Web Application Firewall (WAF) rules to detect and block suspicious access patterns to email log functionality
• Enable WordPress audit logging to track access to sensitive plugin functionality
• Set up alerts for unusual patterns of password reset requests followed by immediate account access

Monitoring Recommendations

• Review Post SMTP plugin version across all WordPress installations in your environment
• Implement real-time monitoring of authentication events and password reset workflows
• Configure alerting for any access to email log endpoints from non-administrative users
• Monitor for bulk or automated requests targeting WordPress AJAX handlers

How to Mitigate CVE-2025-11833

Immediate Actions Required

• Update the Post SMTP plugin to the latest patched version immediately
• Review email logs for any evidence of unauthorized access
• Force password resets for all users if compromise is suspected
• Consider temporarily disabling the Post SMTP plugin if immediate update is not possible

Patch Information

The vulnerability has been addressed in versions after 3.6.0. The fix implements proper capability checks to ensure only authorized users can access email log functionality. The patch can be reviewed in the WordPress Post SMTP Changeset. Site administrators should update to the latest available version through the WordPress plugin repository to receive the security fix.

Additional technical details about the vulnerability are available in the Wordfence Vulnerability Report.

Workarounds

• Restrict access to /wp-admin/admin-ajax.php for unauthenticated users at the web server level if feasible
• Implement IP-based access controls to limit WordPress administrative access to trusted networks
• Configure a Web Application Firewall to block requests to Post SMTP related AJAX actions from unauthenticated sources
• Regularly purge email logs to minimize exposure of sensitive data if the plugin cannot be immediately updated