Contact Form
CVE-2021-24381
MEDIUM
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. |
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Alert meAnalysisAI
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
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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
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
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
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.
What every action level means
SSVC AssessmentENISA
Priority Score
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
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NVD
CVE.org
EPSS
GitHub PoC
Exploit-DB