# CVE-2026-18436: MailerPress <= 1.5.0 - Missing Authorization to Unauthenticated Arbitrary Modification via REST API Endpoint

> Unauthenticated attackers can modify campaign content by restoring arbitrary revisions via an unprotected REST API endpoint in the MailerPress plugin.

- **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:** 31 Jul 2026
- **Updated:** 31 Jul 2026
- **Also known as:** GHSA-vfgx-g9m5-wfgv

## What is CVE-2026-18436?

CVE-2026-18436 is a medium-severity missing authorization vulnerability in MailerPress – Newsletter, email marketing & AI automation, published on 31 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The MailPress plugin for WordPress is vulnerable to unauthorized access in versions up to, and including, 1.5.0 via the campaign revision-restore REST endpoint (POST /wp-json/mailpress/v1/campaign/<id>/restore-revision/<revision_id>). The route in the vulnerable range was registered without a permissionCallback, allowing the restoreRevision() handler to run for unauthenticated requests and overwrite a campaign's content_html with any prior revision. This makes it possible for unauthenticated attackers to modify campaign content by restoring an arbitrary revision.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-18436?


## How do I fix CVE-2026-18436?

No fix has been published for CVE-2026-18436 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-18436 being exploited?

There is no known exploitation of CVE-2026-18436 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18436 and fix it if it is affected.

What it is: CVE-2026-18436 is a medium-severity missing authorization vulnerability in MailerPress – Newsletter, email marketing & AI automation, published on 31 Jul 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-2026-18436 in the wild and no public exploit code.

Affected product: MailerPress – Newsletter, email marketing & AI automation. 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-2026-18436/ (Markdown: https://insights.sbomify.com/CVE-2026-18436/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18436
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18436
- OSV: https://osv.dev/vulnerability/CVE-2026-18436

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-18436/
Summaries are generated and may contain mistakes; the official description above is the record.