Post SMTP <= 3.8.0 - Missing Authorization to Authenticated (Subscriber+) Office 365 OAuth Configuration Overwrite
The Post SMTP plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the handle_office365_oauth_redirect() function in all versions up to, and including, 3.8.0. This is due to the function being hooked to admin_init without any current_user_can() check or nonce verification. This makes it possible for authenticated attackers, with Subscriber-level access and above, to overwrite the site's Office 365 OAuth mail configuration (access token, refresh token, and user email) via a crafted URL. The configuration option is used during wizard setup of Microsoft365 SMTP, only available in the Pro option of the plugin. This could cause an Administrator to believe an attacker-controlled Azure app is their own, and lead them to connect the plugin to the attacker's account during configuration after upgrading to Pro.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| WordPress plugin | Post SMTP – Complete Email Delivery and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App | <= 3.8.0 | 3.9.0 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N- Weakness (CWE)
CWE-862- Platform
- WordPress
- Package
Post SMTP – Complete Email Delivery and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App- Disclosed
- 17.03.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
Wordfence Intelligence - 323436b5-fbfe-4923-8b08-93c1fcabc016 - Wordfence Intelligence
Copyright 1999-2026 The MITRE Corporation
Copyright 2012-2026 Defiant Inc.
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Vulnerability history: Post SMTP – Complete Email Delivery and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App
All published vulnerabilities of this package (WordPress plugin), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 28
- First → latest
- 03.2021 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 2
- High 11
- Medium 15
Disclosures per year
- 2021: 1
- 2022: 2
- 2023: 7
- 2024: 5
- 2025: 7
- 2026: 6
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Post SMTP <= 3.8.0 - Missing Authorization to Authenticated (Subscriber+) Office 365 OAuth Configuration Overwrite this entry
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