POST SMTP Mailer – Email log, Delivery Failure Notifications and Best Mail SMTP for WordPress <= 2.8.7 - Authorization Bypass via type connect-app API

Authorization Bypass Through User-Controlled Key
CVE CVE-2023-6875
CVSS 9.8 (Critical)
Publicly Published January 10, 2024
Last Updated January 22, 2024
Researcher Ulyses Saicha


The POST SMTP Mailer – Email log, Delivery Failure Notifications and Best Mail SMTP for WordPress plugin for WordPress is vulnerable to unauthorized access of data and modification of data due to a type juggling issue on the connect-app REST endpoint in all versions up to, and including, 2.8.7. This makes it possible for unauthenticated attackers to reset the API key used to authenticate to the mailer and view logs, including password reset emails, allowing site takeover. CVE-2023-52233 appears to be a duplicate of this issue.

Wordfence blocked 28,276 attacks targeting this vulnerability in the past 24 hours.



Vulnerability Details for Post SMTP – WordPress SMTP Plugin with Email Logs and Mobile App for Failure Notifications – Gmail SMTP, Office 365, Brevo, Mailgun, Amazon SES and more

Software Type Plugin
Software Slug post-smtp (view on
Patched? Yes
Remediation Update to version 2.8.8, or a newer patched version
Affected Version
  • <= 2.8.7
Patched Version
  • 2.8.8

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