# CVE-2026-6675: Responsive Blocks <= 2.2.0 - Unauthenticated Open Email Relay via REST API 'email_to' Parameter

> Unauthenticated attackers can send arbitrary emails via the REST API, turning the site into an open mail relay.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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:** 21 Apr 2026
- **Updated:** 21 Apr 2026
- **Also known as:** GHSA-jqqm-hx2h-83c5

## What is CVE-2026-6675?

CVE-2026-6675 is a medium-severity vulnerability in cyberchimps Responsive Blocks – Page Builder for Blocks & Patterns, published on 21 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Responsive Blocks – Page Builder for Blocks & Patterns plugin for WordPress is vulnerable to Unauthenticated Open Email Relay in all versions up to, and including, 2.2.0. This is due to insufficient authorization checks and missing server-side validation of the recipient email address supplied via a public REST API route. This makes it possible for unauthenticated attackers to send arbitrary emails to any recipient of their choosing through the affected WordPress site's mail server, effectively turning the site into an open mail relay.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-6675?


## How do I fix CVE-2026-6675?

No fix has been published for CVE-2026-6675 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-6675 being exploited?

There is no known exploitation of CVE-2026-6675 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-6675 and fix it if it is affected.

What it is: CVE-2026-6675 is a medium-severity vulnerability in cyberchimps Responsive Blocks – Page Builder for Blocks & Patterns, published on 21 Apr 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-2026-6675 in the wild and no public exploit code.

Affected product: cyberchimps Responsive Blocks – Page Builder for Blocks & Patterns. 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-2026-6675/ (Markdown: https://insights.sbomify.com/CVE-2026-6675/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-6675
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6675
- OSV: https://osv.dev/vulnerability/CVE-2026-6675

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-6675/
Summaries are generated and may contain mistakes; the official description above is the record.