FluentSMTP <= 2.2.95 - Unauthenticated Stored Cross-Site Scripting via Recipient Display Name (to.name) in Email Logs

7.2
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE CVE-2026-16636
CVSS 7.2 (High)
Publicly Published August 5, 2026
Last Updated August 6, 2026
Researcher Fraudless - Fraudless.tech

Description

The FluentSMTP – WP SMTP Plugin with Amazon SES, SendGrid, MailGun, Postmark, Google and Any SMTP Provider plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Recipient Display Name (to.name) in Email Logs in all versions up to, and including, 2.2.95 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. The payload is delivered via an attacker-controlled recipient display name (to.name) in a wp_mail() call and does not fire in the log list view — only in the detail view when an administrator uses the Prev/Next navigation controls, as that path bypasses the escapeHtml pipeline used by the list view.

Learn more about Cross-Site Scripting vulnerabilities and how to prevent them.

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Vulnerability Details for FluentSMTP – WP SMTP Plugin with Amazon SES, SendGrid, Mailgun, Postmark, Cloudflare, toSend, Gmail and Any SMTP

Software Type Plugin
Software Slug fluent-smtp (view on wordpress.org)
Patched? Yes
Remediation Update to version 2.3.0, or a newer patched version
Affected Version
  • <= 2.2.95
Patched Version
  • 2.3.0

Recent vulnerabilities in FluentSMTP – WP SMTP Plugin with Amazon SES, SendGrid, Mailgun, Postmark, Cloudflare, toSend, Gmail and Any SMTP

# Title CVE ID CVSS Researchers Date
1 FluentSMTP <= 2.2.80 - Cross-Site Request Forgery CVE-2025-24739 4.3 Rafie Muhammad January 24, 2025
2 FluentSMTP – WP SMTP Plugin with Amazon SES, SendGrid, MailGun, Postmark, Google and Any SMTP Provider <= 2.2.82 - Unauthenticated PHP Object Injection CVE-2024-9511 9.8 Leo November 22, 2024
3 FluentSMTP <= 2.2.4 - Unauthenticated Stored Cross-Site Scripting via Email Subject CVE-2023-3087 7.2 Alex Thomas July 6, 2023
4 FluentSMTP <= 2.2.2 - Authenticated (Author+) Stored Cross-Site Scripting via Email Logs CVE-2023-0219 3.8 Vaibhav Rajput March 3, 2023
5 FluentSMTP <= 2.0.0 - Authenticated (Admin+) Stored Cross-Site Scripting CVE-2021-24528 5.5 YoshiKen July 29, 2021

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