Post SMTP – Complete SMTP Solution with Logs, Alerts, Backup SMTP & Mobile App <= 3.6.1 - Missing Authorization to Authenticated (Subscriber+) OAuth Token Update
Strategic Overview
- Status
- Patched in 3.6.2
- Affected Plugin
- Post SMTP – Complete Email Deliverability and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App
- Affected Version
<= 3.6.1- CVSS
- 5.4Medium
- Weakness type
- CWE-862 · Missing Authorization
- CVE
CVE-2025-12887
At a glance
CVE-2025-12887 is a medium-severity Missing Authorization vulnerability in the Post SMTP WordPress plugin, affecting versions <= 3.6.1. It carries a CVSS score of 5.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Subscriber level or above. The issue is fixed in version 3.6.2; sites on affected versions should update now. Disclosed December 2025, reported by type5afe.
Vulnerability Overview
The Post SMTP plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 3.6.1. This is due to the plugin not properly verifying that a user is authorized to update OAuth tokens on the 'handle_gmail_oauth_redirect' function. This makes it possible for authenticated attackers, with subscriber level access and above, to inject invalid or attacker-controlled OAuth credentials. CVE-2025-67563 appears to be a duplicate of this issue.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user.
CWE-862: Missing Authorization
Post SMTP <= 3.6.1 carries this weakness at handle_gmail_oauth_redirect, and reaching it takes an account at Subscriber level or above. A missing authorization check means a function is reachable by anyone who can reach the endpoint, because the code never asks whether the caller is allowed to perform the action.
Any user who can reach the endpoint gets to run an action reserved for higher-privileged roles, from reading protected data to changing settings or content. For Post SMTP the fix is 3.6.2: builds <= 3.6.1 are affected, anything from 3.6.2 onward is not.
Remediation
Update to version 3.6.2, or a newer patched version
How does WordSec protect against this?
Because it turns on account access, WordSec's login security is the relevant layer: role-based two-factor, captcha and brute-force limits raise the cost of getting the account this needs. None of that substitutes for the fix: Post SMTP 3.6.2 closes this, and updating the plugin is the step that ends it.
- Login Security
- Alerts
External References
Related records
Same weakness class
- 9.8CVE-2025-11833: Post SMTP Account Takeover
CVE-2025-11833 - 8.8CVE-2025-24000: Post SMTP Authenticated (Subscriber+) Account Takeover
CVE-2025-24000 - 6.3CVE-2026-81278: Post SMTP Authenticated (Subscriber+) Settings Change
CVE-2026-81278 - 5.3CVE-2026-2559: Post SMTP Authenticated (Subscriber+) Office 365 OAuth
CVE-2026-2559
Other vulnerabilities in Post SMTP – Complete Email Deliverability and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App
- 9.8CVE-2023-6875: POST SMTP Mailer Authorization Bypass
CVE-2023-6875 - 7.2CVE-2026-48838: Post SMTP Stored XSS
CVE-2026-48838 - 7.2CVE-2026-3090: Post SMTP <= 3.8.0 Stored Cross-Site Scripting
CVE-2026-3090 - 7.2CVE-2025-0521: Post SMTP <= 3.0.2 Stored Cross-Site Scripting
CVE-2025-0521 - 7.2CVE-2024-5207: POST SMTP Mailer SQL Injection
CVE-2024-5207 - 7.2CVE-2023-7027: POST SMTP Mailer Stored XSS
CVE-2023-7027 - 7.2CVE-2023-6620: POST SMTP Mailer SQL Injection
CVE-2023-6620 - 7.2CVE-2023-5958: POST SMTP Mailer <= 2.7.0 Stored Cross-Site Scripting
CVE-2023-5958
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