# CVE-2026-16636: FluentSMTP <= 2.2.95 - Unauthenticated Stored Cross-Site Scripting via Recipient Display Name (to.name) in Email Logs

> Unauthenticated attackers can inject scripts via recipient display names in email logs, potentially compromising administrator accounts.

- **Severity:** High 7.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 Aug 2026
- **Updated:** 6 Aug 2026
- **Also known as:** GHSA-v4r4-2fwc-5qq5

## What is CVE-2026-16636?

CVE-2026-16636 is a high-severity cross-site scripting vulnerability in wpmanageninja FluentSMTP – WP SMTP Plugin with Amazon SES, SendGrid, Mailgun, Postmark, Cloudflare, toSend, Gmail and Any SMTP, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-16636?


## How do I fix CVE-2026-16636?

No fix has been published for CVE-2026-16636 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-16636 being exploited?

There is no known exploitation of CVE-2026-16636 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-16636 and fix it if it is affected.

What it is: CVE-2026-16636 is a high-severity cross-site scripting vulnerability in wpmanageninja FluentSMTP – WP SMTP Plugin with Amazon SES, SendGrid, Mailgun, Postmark, Cloudflare, toSend, Gmail and Any SMTP, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-16636 in the wild and no public exploit code.

Affected product: wpmanageninja FluentSMTP – WP SMTP Plugin with Amazon SES, SendGrid, Mailgun, Postmark, Cloudflare, toSend, Gmail and Any SMTP. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-16636/ (Markdown: https://insights.sbomify.com/CVE-2026-16636/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-16636
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-16636
- OSV: https://osv.dev/vulnerability/CVE-2026-16636

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-16636/
Summaries are generated and may contain mistakes; the official description above is the record.