Auth bypass in Mailerlite – Signup Forms (Official)

CVE-2026-3253

The MailerLite – Signup forms (official) plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the forms() method of the AdminController class in all versions up to, and including, 1.7.21. This makes it possible for authenticated attackers, with Contributor-level access and above, to create or delete arbitrary signup forms.

Vulnerability class: Broken Access Control

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (8.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 8.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-3253: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-3253?
CVE-2026-3253 is a medium-severity vulnerability in Mailerlite – Signup Forms (Official), classified under Missing Authorization. CVSS score: 4.3/10. Published 2026-09-24.
How severe is CVE-2026-3253?
Medium severity. CVSS v3 base score is 4.3 out of 10.