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.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
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
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.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-18436 being exploited?
There is no known exploitation of CVE-2026-18436 in the wild and no public exploit code.
Sources
Also known as GHSA-vfgx-g9m5-wfgv.