MailerPress <= 1.5.0 - Missing Authorization to Unauthenticated Arbitrary Modification via REST API Endpoint
Strategic Overview
- Status
- Patched in 1.5.1
- Affected Version
<= 1.5.0- CVSS
- 5.3Medium
- Weakness type
- CWE-862 · Missing Authorization
- CVE
CVE-2026-18436
At a glance
CVE-2026-18436 is a medium-severity Missing Authorization vulnerability in the MailerPress WordPress plugin, affecting versions <= 1.5.0. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 1.5.1; sites on affected versions should update now. Disclosed July 2026, reported by Jakub Lipiński (A3RES).
Vulnerability Overview
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.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.
CWE-862: Missing Authorization
MailerPress <= 1.5.0 carries this weakness at restoreRevision(), and reaching it takes no account at all. A missing authorization check means a function is reachable by anyone who can reach the endpoint, because the code never asks whether the caller is allowed to perform the action.
Any user who can reach the endpoint gets to run an action reserved for higher-privileged roles, from reading protected data to changing settings or content. For MailerPress the fix is 1.5.1: builds <= 1.5.0 are affected, anything from 1.5.1 onward is not.
Remediation
Update to version 1.5.1, or a newer patched version
How does WordSec protect against this?
This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: MailerPress 1.5.1 closes this, and updating the plugin is the step that ends it.
- Login Security
- Alerts
External References
Related records
Same weakness class
Other vulnerabilities in MailerPress – Email Marketing, Newsletter, Email Automation & WooCommerce Emails
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