CVE-2026-100155

Ninja Forms <= 3.15.5 - Unauthenticated Arbitrary Shortcode Execution via 'formData' Field Value via Success Message Merge Tag

6.5 Medium

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: Low
Availability: None

Exploit likelihood

0.51%Unchanged since Oct 31, 2026

What each source reports

CVE List Score used 6.5

Ninja Forms <= 3.15.5 - Unauthenticated Arbitrary Shortcode Execution via 'formData' Field Value via Success Message Merge Tag

Record: CVE-2026-100155
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Weakness: CWE-94
Updated: 2026-11-02

EUVDEUVD-2026-114578 6.5

Record: EUVD-2026-114578
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-pqjx-p6p5-mv3f 6.5

The The Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form...

Record: GHSA-pqjx-p6p5-mv3f
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Weakness: CWE-94
Updated: 2026-11-02

NVD 6.5

Record: CVE-2026-100155
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Weakness: CWE-94
Updated: 2026-11-02

Affected products

kstover ninja forms – contact form builder with calculators, quizzes, signatures & ai form builder

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-100155 is a medium vulnerability (CVSS 6.5) in Kstover Ninja Forms – Contact Form Builder With Calculators, Quizzes, Signatures & Ai Form Builder, published October 31, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.51%, the 44th percentile. No source names a fixed version.