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Contact Form CVE-2021-24381

MEDIUM
Cross-site Scripting (XSS) (CWE-79)
2021-10-25 contact@wpscan.com
4.8
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK

2 techniques across 2 tactics: Initial Access, Execution

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

Impact

CVSS score of 4.8 (MEDIUM). Attack characteristics: network attack vector, low complexity, high privileges required, user interaction required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

A remote attacker could inject malicious scripts into web pages viewed by other users by sending crafted requests to the affected application.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.6% exploitation probability (EPSS)

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AnalysisAI

The Ninja Forms Contact Form WordPress plugin before 3.5.8.2 does not sanitise and escape the custom class name of the form field created, which could allow high privilege users to perform Cross-Site. Rated medium severity (CVSS 4.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.

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 Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. The Ninja Forms Contact Form WordPress plugin before 3.5.8.2 does not sanitise and escape the custom class name of the form field created, which could allow high privilege users to perform Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed. Affected products include: Ninjaforms Contact Form. Version information: before 3.5.8.2.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 4.8 MEDIUM
AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

DescriptionNVD

The Ninja Forms Contact Form WordPress plugin before 3.5.8.2 does not sanitise and escape the custom class name of the form field created, which could allow high privilege users to perform Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed.

Threat Intelligence Overview

EPSS Score
0.6%
Top 56% 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 No
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

45
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +24
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.

Affected Products (CPE)NVD

cpe:2.3:a:ninjaforms:contact_form:*:*:*:*:*:wordpress:*:*
CVE-2024-2771 CRITICAL POC
9.8 May 18

The Contact Form Plugin by Fluent Forms for Quiz, Survey, and Drag & Drop WP Form Builder plugin for WordPress is vulner

CVE-2022-3463 CRITICAL POC
9.8 Nov 07

The Contact Form Plugin WordPress plugin before 4.3.13 does not validate and escape fields when exporting form entries a

CVE-2024-2782 HIGH POC
7.5 May 18

The Contact Form Plugin by Fluent Forms for Quiz, Survey, and Drag & Drop WP Form Builder plugin for WordPress is vulner

CVE-2021-34620 HIGH POC
8.8 Jul 07

The WP Fluent Forms plugin < 3.6.67 for WordPress is vulnerable to Cross-Site Request Forgery leading to stored Cross-Si

CVE-2019-11591 HIGH POC
8.8 Apr 29

The WebDorado Contact Form plugin before 1.13.5 for WordPress allows CSRF via the wp-admin/admin-ajax.php action paramet

CVE-2019-25145 HIGH POC
7.2 Jun 07

The Contact Form & SMTP Plugin by PirateForms plugin for WordPress is vulnerable to HTML injection in the ‘public/class-

CVE-2024-9651 MEDIUM POC
6.1 Dec 09

The Fluent Forms WordPress plugin before 5.2.1 does not sanitise and escape some of its settings, which could allow high

CVE-2021-24276 MEDIUM POC
6.1 May 05

The Contact Form by Supsystic WordPress plugin before 1.7.15 did not sanitise the tab parameter of its options page befo

CVE-2023-0546 MEDIUM POC
5.4 Apr 10

The Contact Form Plugin WordPress plugin before 4.3.25 does not properly sanitize and escape the srcdoc attribute in ifr

CVE-2020-10385 MEDIUM POC
5.4 Mar 24

A stored cross-site scripting (XSS) vulnerability exists in the WPForms Contact Form (aka wpforms-lite) plugin before 1.

CVE-2023-45068 HIGH
8.8 Oct 12

Cross-Site Request Forgery (CSRF) vulnerability in Supsystic Contact Form by Supsystic plugin <= 1.7.27 versions. Rated

CVE-2023-44231 HIGH
8.8 Oct 09

Cross-Site Request Forgery (CSRF) vulnerability in NickDuncan Contact Form plugin <= 2.0.10 versions. Rated high severit

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