What’s Vulnerable › Vulnerabilities

CVE-2023-3087: FluentSMTP <= 2.2.4 - Unauthenticated Stored Cross-Site Scripting via Email Subject

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-07-12 · updated 2026-06-17
• Weakness: CWE-79

Description

The FluentSMTP plugin for WordPress is vulnerable to Stored Cross-Site Scripting via an email subject in versions up to, and including, 2.2.4 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Affected products

• techjewel FluentSMTP – WP SMTP Plugin with Amazon SES, SendGrid, MailGun, Postmark, Google and Any SMTP Provider: before 2.2.5 — fixed in 2.2.5

How to fix

Upgrade to a fixed version: techjewel FluentSMTP – WP SMTP Plugin with Amazon SES, SendGrid, MailGun, Postmark, Google and Any SMTP Provider 2.2.5. Check the vendor advisory for mitigations.

References

• https://plugins.trac.wordpress.org/changeset/2935217/fluent-smtp/trunk/app/Models/Logger.php
• https://plugins.trac.wordpress.org/changeset/2935217/fluent-smtp/trunk/app/Services/Mailer/BaseHandler.php
• https://www.wordfence.com/threat-intel/vulnerabilities/id/fa47a794-e5ce-491d-a10b-c7c5718aa853?source=cve
• https://plugins.trac.wordpress.org/changeset/2935217/fluent-smtp/trunk/app/Models/Logger.php
• https://plugins.trac.wordpress.org/changeset/2935217/fluent-smtp/trunk/app/Services/Mailer/BaseHandler.php
• https://www.wordfence.com/threat-intel/vulnerabilities/id/fa47a794-e5ce-491d-a10b-c7c5718aa853?source=cve

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