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Ninja Forms <= 3.6.25 — Denial of Service via Large Form Submissions

CVE-2023-35909Published · Updated

Action summary

Affected: ≤3.6.25Update to 3.6.26 or newer

All remediation steps
Watch plugin
Severity
Medium5.3
CVSS
5.3
CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
What does this vector mean?
AV:N Attack vector
Network
AC:L Attack complexity
Low
PR:N Privileges required
None
UI:N User interaction
None
S:U Scope
Unchanged
C:N Confidentiality
None
I:N Integrity
None
A:L Availability
Low
Weakness
CWE-400 Uncontrolled Resource Consumption
Required access
No account needed
Exploit prediction (EPSS)
No score
CISA KEV
Not listed
On this page8

Am I affected?

Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder ninja-forms

  1. Affected≤ 3.6.25
  2. Patched in3.6.26

Update to 3.6.26 or newer.

You are affected if you run ≤ 3.6.25. Version 3.6.26 and later are not affected by this issue.

  • Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder.
  • No admin access? Run a passive check of your site. It reads public files only.
  • No account is needed to exploit this. Treat any exposed site on an affected version as at risk.

What to do

  1. Update to version 3.6.26, or a newer patched version
  2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
  3. Watch Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to PetiteMais.

The Ninja Forms plugin for WordPress is vulnerable to denial of service in versions up to, and including, 3.6.25. This is due to insufficient controls on form submissions. This makes it possible for unauthenticated attackers to craft form submissions with excessive extra data that may exceed the capacity of the database and prevent further requests from being successful while the submission is processing.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

More in Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder

All 95
More vulnerabilities in Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder
SeverityVulnerabilityCVEPublished
Medium6.1Reflected DOM-Based Cross-Site Scripting via 'querystring:<key>' URL Parameter
≤3.15.5Update to 3.15.6
CVE-2026-100151
Medium6.5Unauthenticated Arbitrary Shortcode Execution via 'formData' Field Value via Success Message Merge Tag
≤3.15.5Update to 3.15.6
CVE-2026-100155
Medium5.4Authenticated (Subscriber+) Arbitrary Shortcode Execution via '{wp:user_display_name}' Merge Tag via display_name
≤3.15.5Update to 3.15.6
CVE-2026-101326
High7.2Unauthenticated Stored Cross-Site Scripting via 'extra' Parameter via Metadata Key Normalization
≤3.15.5Update to 3.15.6
CVE-2026-109997
Medium5.8Unauthenticated CSV Injection
≤3.15.3Update to 3.15.4
CVE-2026-67187

Timeline

  1. CVE published

    Severity medium, CVSS 5.3

  2. Record last updated

Sources & licenses

Wordfence record
Vulnerability data
Wordfence Intelligence. [object Object] Licensed under the CC BY-SA 4.0.
CVE® identifiers
[object Object]. Used under the CVE Program. CVE® is a registered trademark of The MITRE Corporation.
CVSS / CWE
National Vulnerability Database (NVD), shown unmodified. This product uses the NVD API but is not endorsed or certified by the NVD.
VulnCrest content
Summary, remediation guidance and page layout © VulnCrest. Not sourced from NVD.

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