Subscriber-level OAuth configuration overwrite via unchecked redirect
Published Mar 18, 2026 · Updated Mar 18, 2026
Missing authorization in WPExperts Post SMTP 3.8.0 and earlier allows remote authenticated users to overwrite Office 365 OAuth configuration. The handle_office365_oauth_redirect() handler runs on admin_init without a capability check or nonce validation and accepts crafted URL values for the access token, refresh token, and user email. Subscriber-level access is sufficient, but the stored values matter only during Microsoft 365 wizard setup in the Pro edition, where they can mislead an administrator into connecting an attacker-controlled Azure app.
Summary
What happened
Missing authorization in WPExperts Post SMTP 3.8.0 and earlier allows remote authenticated users to overwrite Office 365 OAuth configuration. The handle_office365_oauth_redirect() handler runs on admin_init without a capability check or nonce validation and accepts crafted URL values for the access token, refresh token, and user email. Subscriber-level access is sufficient, but the stored values matter only during Microsoft 365 wizard setup in the Pro edition, where they can mislead an administrator into connecting an attacker-controlled Azure app.
The record
- CVE
- CVE-2026-2559
- Published
- Mar 18, 2026
- Updated
- Mar 18, 2026
- Vendor
- WPExperts
- Product
- Post SMTP
- Classifications
- CWE-862, T1565.001
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 18, 2026CVE publishedPublication date reported by the CVE source.
- Mar 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=* <=3.8.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
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Your stack
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