Description

Missing Authorization vulnerability in WPExperts Post SMTP allows Exploiting Incorrectly Configured Access Control Security Levels. This issue affects Post SMTP: from 4.0.0 through beta.1.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.4",
  "pubDate": "2026-08-31T21:17:49.550Z",
  "pubdate": "2026-08-31T21:17:49.550Z",
  "executiveSummary": "This vulnerability involves a Missing Authorization flaw within the WPExperts Post SMTP plugin, identified in versions 4.0.0 through beta.1.\nThe security defect stems from incorrectly configured access control security levels, which allows unauthorized users to perform sensitive actions.\nThe vulnerability type is classified as Improper Authorization, which can lead to unauthorized information disclosure or modification of plugin settings.\nThe affected system is the Post SMTP plugin for WordPress. Attackers do not necessarily require high-level administrative privileges to exploit this flaw, as the missing authorization checks bypass the intended restriction mechanisms.\nThe risk implication is significant as the plugin manages email delivery and configuration, potentially allowing an attacker to intercept email communication or manipulate SMTP credentials.\nExploitation requires no complex conditions beyond network access to the target WordPress instance, as the lack of robust access control checks allows requests to proceed without validating the requester's identity or authorization status.",
  "technicalDetails": "The vulnerability manifests due to a failure to implement proper access control checks within the core functionality of the Post SMTP plugin, specifically within the affected range of 4.0.0 through beta.1.\nIn a secure configuration, administrative endpoints or sensitive plugin operations should perform a strict check of the user's capabilities, typically utilizing the WordPress current_user_can() function to verify if the requestor possesses the manage_options or equivalent capability.\nThe identified flaw indicates that these authorization hooks are either missing, improperly implemented, or incorrectly configured in the plugin's request handling logic. This allows a remote attacker to send specifically crafted HTTP requests to the plugin's endpoints, effectively bypassing security filters intended to limit access to sensitive configuration parameters.\nThe attack flow typically involves an unauthorized actor identifying the target API or administrative action endpoint within the Post SMTP plugin. Since the authorization check is absent, the server-side code executes the requested operation regardless of the session context or user role. Consequently, an attacker can modify SMTP configuration settings, such as the SMTP host, port, username, or password, or access logs containing sensitive transit data.\nThis vulnerability is rooted in the incorrect application of access control security levels, meaning the codebase fails to enforce the principle of least privilege. By omitting the mandatory capability checks, the plugin effectively treats all incoming requests as authorized.\nThe post-exploitation impact is severe. By manipulating the SMTP settings, an attacker can redirect email traffic through a malicious server, facilitating Man-in-the-Middle (MitM) attacks, credential theft, or the interception of sensitive password reset emails. Because the plugin interfaces with mail transport protocols, the exploitation can lead to a total compromise of the application's email communication channel. Furthermore, the lack of authentication allows for enumeration or unauthorized modification of plugin settings that are otherwise reserved for administrators.\nThere are no complex payloads required; the exploit relies on the structural absence of authentication, allowing standard HTTP GET or POST requests to reach internal handlers that should have remained restricted."
}