Post SMTP <= 3.8.0 - Missing Authorization to Authenticated (Subscriber+) Office 365 OAuth Configuration Overwrite
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · High · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-862.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| saadiqbal | Post SMTP – Complete Email Deliverability and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App | up to 3.8.0 | — | No fix listed | CNA |
- Post SMTP – Complete Email Deliverability and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App Vendorsaadiqbal Affected up to 3.8.0 Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-2559
- 2026-10-03 Alias added: GHSA-gmrm-qq98-m6xv
References
Other 4
- https://www.wordfence.com/threat-intel/vulnerabilities/id/323436b5-fbfe-4923-8b08-93c1fcabc016?source=cve
- https://plugins.trac.wordpress.org/browser/post-smtp/trunk/Postman/Wizard/NewWizard.php#L2109
- https://plugins.trac.wordpress.org/browser/post-smtp/trunk/Postman/Wizard/NewWizard.php#L104
- https://plugins.trac.wordpress.org/changeset/3484515/
More saadiqbal vulnerabilities
- TI-2025-10849 Missing authorization in saadiqbal Post SMTP – Complete Email Deliverability and SMTP… CVSS 3.1CRITICAL 9.8
- TI-2024-29006 WordPress myCred plugin <= 2.7.2 - PHP Object Injection vulnerability CVSS 3.1CRITICAL 9.8
- TI-2025-36263 WordPress All In One Login plugin <= 2.0.8 - Bypass Vulnerability vulnerability CVSS 3.1CRITICAL 9.1
- TI-2026-05814 WPFormify <= 1.1.1 - Missing Authorization CVSS 3.1HIGH 8.2
- TI-2025-42518 WordPress New User Approve plugin <= 3.2.0 - Broken Access Control vulnerability CVSS 3.1HIGH 8.6
- TI-2024-35074 WordPress User Management plugin <= 1.1 - Arbitrary File Upload vulnerability CVSS 3.1CRITICAL 9.9
Sources
- CVE-2026-2559 · CVE Program
- CVE-2026-2559 · NVD
- FIRST EPSS
- GHSA-gmrm-qq98-m6xv · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences