CVE-2023-35909

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

2023-07-07 00:00

Strategic Overview

Status: Patched in 3.6.26
Affected Plugin: Ninja Forms – The Contact Form Builder That Grows With You
Affected Version: <= 3.6.25
CVSS: 5.3Medium
Weakness type: CWE-400 · Uncontrolled Resource Consumption
CVE: CVE-2023-35909

View all Ninja Forms – The Contact Form Builder That Grows With You vulnerabilities

At a glance

CVE-2023-35909 is a medium-severity Uncontrolled Resource Consumption vulnerability in the Ninja Forms WordPress plugin, affecting versions <= 3.6.25. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 3.6.26; sites on affected versions should update now. Disclosed July 2023, reported by PetiteMais.

Vulnerability Overview

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.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.

CWE-400: Uncontrolled Resource Consumption

Reaching this weakness in Ninja Forms <= 3.6.25 takes a caller who can reach the endpoint. Uncontrolled resource consumption means a request can make the server do an amount of work it never bounds, because the size or repetition of the job is taken from the request rather than capped by the code.

A single caller can hold PHP workers, database connections or disk open long enough to slow the site for everyone, without needing any account or any other flaw. For Ninja Forms the fix is 3.6.26: builds <= 3.6.25 are affected, anything from 3.6.26 onward is not.

Remediation

Update to version 3.6.26, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Ninja Forms: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Ninja Forms 3.6.26 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2023-35909 https://www.wordfence.com/threat-intel/vulnerabilities/id/952a3e52-4e23-4bc4-92d3-e15ae2f3d28b https://nvd.nist.gov/vuln/detail/CVE-2023-35909

Related records

Other vulnerabilities in Ninja Forms – The Contact Form Builder That Grows With You

CVSS Vector

5.3

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityLow

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