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Ninja Forms CVE-2021-34648

MEDIUM
Incorrect Authorization (CWE-863)
2021-09-22 security@wordfence.com
4.3
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization logic validation
MITRE ATT&CK

1 technique across 1 tactic: Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 4.3 (MEDIUM). Attack characteristics: network attack vector, low complexity, low privileges required, no user interaction not required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

A remote attacker could bypass authorization checks to access restricted resources by sending crafted requests to the affected application.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.6% exploitation probability (EPSS)

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AnalysisAI

The Ninja Forms WordPress plugin is vulnerable to arbitrary email sending via the trigger_email_action function found in the ~/includes/Routes/Submissions.php file, in versions up to and including. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Review and test authorization logic, implement consistent access control checks, use centralized authorization framework.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Incorrect Authorization (CWE-863), which allows attackers to bypass authorization checks to access restricted resources. The Ninja Forms WordPress plugin is vulnerable to arbitrary email sending via the trigger_email_action function found in the ~/includes/Routes/Submissions.php file, in versions up to and including 3.5.7. This allows authenticated attackers to send arbitrary emails from the affected server via the /ninja-forms-submissions/email-action REST API which can be used to socially engineer victims. Affected products include: Ninjaforms Ninja Forms.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 4.3 MEDIUM
AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

DescriptionNVD

The Ninja Forms WordPress plugin is vulnerable to arbitrary email sending via the trigger_email_action function found in the ~/includes/Routes/Submissions.php file, in versions up to and including 3.5.7. This allows authenticated attackers to send arbitrary emails from the affected server via the /ninja-forms-submissions/email-action REST API which can be used to socially engineer victims.

Threat Intelligence Overview

EPSS Score
0.6%
Top 54% exploitable
Exploit
POC
Public exploit code exists
Data Quality
2 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC Yes
EPSS 0.6%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

43
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +22
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Affected Products (CPE)NVD

cpe:2.3:a:ninjaforms:ninja_forms:*:*:*:*:*:wordpress:*:*
CVE-2016-1209 CRITICAL POC
9.8 May 14

The Ninja Forms plugin before 2.9.42.1 for WordPress allows remote attackers to conduct PHP object injection attacks via

CVE-2026-92438 HIGH POC
8.8 Sep 22

Stored cross-site scripting in the Ninja Forms WordPress plugin 3.15.3 lets an unauthenticated visitor plant a script pa

CVE-2021-24163 HIGH POC
8.8 Apr 05

The AJAX action, wp_ajax_ninja_forms_sendwp_remote_install_handler, did not have a capability check on it, nor did it ha

CVE-2018-16308 HIGH POC
8.6 Sep 01

The Ninja Forms plugin before 3.3.14.1 for WordPress allows CSV injection. Rated high severity (CVSS 8.6), this vulnerab

CVE-2026-91827 HIGH POC
7.5 Sep 22

PHP Object Injection in the Ninja Forms WordPress plugin 3.15.3 allows unauthenticated attackers to plant serialized pay

CVE-2022-2903 HIGH POC
7.2 Sep 26

The Ninja Forms Contact Form WordPress plugin before 3.6.13 unserialises the content of an imported file, which could le

CVE-2021-24889 HIGH POC
7.2 Nov 29

The Ninja Forms Contact Form WordPress plugin before 3.6.4 does not escape keys of the fields POST parameter, which coul

CVE-2021-34647 MEDIUM POC
6.5 Sep 22

The Ninja Forms WordPress plugin is vulnerable to sensitive information disclosure via the bulk_export_submissions funct

CVE-2024-7354 MEDIUM POC
6.1 Sep 02

The Ninja Forms WordPress plugin before 3.8.11 does not escape an URL before outputting it back in an attribute, leading

CVE-2023-37979 MEDIUM POC
6.1 Jul 27

Unauth. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low at

CVE-2023-1835 MEDIUM POC
6.1 May 15

The Ninja Forms Contact Form WordPress plugin before 3.6.22 does not properly escape user input before outputting it bac

CVE-2021-24165 MEDIUM POC
6.1 Apr 05

In the Ninja Forms Contact Form WordPress plugin before 3.4.34, the wp_ajax_nf_oauth_connect AJAX action was vulnerable

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