CVE-2023-6629: POST SMTP Mailer <= 2.8.6 - Reflected Cross-Site Scripting via msg

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-01-03 · updated 2026-06-17
Weakness: CWE-79

Description

The POST SMTP Mailer – Email log, Delivery Failure Notifications and Best Mail SMTP for WordPress plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the ‘msg’ parameter in all versions up to, and including, 2.8.6 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. CVE-2023-6621 appears to be a duplicate of this issue. CVE-2024-29128 appears to be a duplicate of this issue.

Affected products

saadiqbal Post SMTP – Complete Email Deliverability and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App: before 2.8.7 — fixed in 2.8.7

How to fix

Upgrade to a fixed version: saadiqbal Post SMTP – Complete Email Deliverability and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App 2.8.7. Check the vendor advisory for mitigations.

References

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