XSS in Wpmanageninja Fluentsmtp – Wp Smtp Plugin With Amazon Ses, Sendgrid, Mailgun, Postmark, Cloudflare, Tosend, Gmail And Any

CVE-2026-16636

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.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.005 (44.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 44.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-16636: held from 0.005 to 0.005.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-16636?
CVE-2026-16636 is a high-severity vulnerability in Wpmanageninja Fluentsmtp – Wp Smtp Plugin With Amazon Ses, Sendgrid, Mailgun, Postmark, Cloudflare, Tosend, Gmail And Any, classified under Cross-site Scripting. CVSS score: 7.2/10. Published 2026-08-06.
How severe is CVE-2026-16636?
High severity. CVSS v3 base score is 7.2 out of 10.