# CVE-2026-8599: MailerPress <= 2.0.4 - Authenticated (Author+) Stored Cross-Site Scripting via Campaign HTML Content Field

> Authenticated attackers with author-level access can inject arbitrary scripts into campaign HTML content, executing them in the admin dashboard.

- **Severity:** Medium 6.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Jun 2026
- **Updated:** 9 Jun 2026
- **Also known as:** GHSA-9jw9-xmq5-9839

## What is CVE-2026-8599?

CVE-2026-8599 is a medium-severity cross-site scripting vulnerability in MailerPress – Email Marketing, Newsletter, Email Automation & WooCommerce Emails, published on 9 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

The MailerPress – Email Marketing, Newsletter, Email Automation & WooCommerce Emails plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Campaign HTML Content Field in all versions up to, and including, 2.0.4 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The public-facing campaign preview endpoint (/mp-email/{id}-slug/) is not affected by this vulnerability, as it applies a Content-Security-Policy header blocking all inline scripts; exploitation is limited to the admin dashboard preview.

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

## Which versions are affected by CVE-2026-8599?


## How do I fix CVE-2026-8599?

No fix has been published for CVE-2026-8599 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-8599 being exploited?

There is no known exploitation of CVE-2026-8599 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-8599 and fix it if it is affected.

What it is: CVE-2026-8599 is a medium-severity cross-site scripting vulnerability in MailerPress – Email Marketing, Newsletter, Email Automation & WooCommerce Emails, published on 9 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-8599 in the wild and no public exploit code.

Affected product: MailerPress – Email Marketing, Newsletter, Email Automation & WooCommerce Emails. 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-2026-8599/ (Markdown: https://insights.sbomify.com/CVE-2026-8599/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-8599
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-8599
- OSV: https://osv.dev/vulnerability/CVE-2026-8599

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-8599/
Summaries are generated and may contain mistakes; the official description above is the record.