RCE in Kstover Ninja Forms – Contact Form Builder With Calculators, Quizzes, Signatures & Ai

CVE-2026-100155

The The Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder plugin for WordPress is vulnerable to arbitrary shortcode execution in all versions up to, and including, 3.15.5 This is due to the software allowing users to execute an action that does not properly validate a value before running do_shortcode. This makes it possible for unauthenticated attackers to execute arbitrary shortcodes.

Vulnerability class: RCE (Remote Code Execution)

Published .

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.005 (43.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 44th percentile — 43.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

The 30-day trend appears once there are two daily scores.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-100155?
CVE-2026-100155 is a medium-severity vulnerability in Kstover Ninja Forms – Contact Form Builder With Calculators, Quizzes, Signatures & Ai, classified under Code Injection. CVSS score: 6.5/10. Published 2026-10-31.
How severe is CVE-2026-100155?
Medium severity. CVSS v3 base score is 6.5 out of 10.