CVE-2021-24381: NinjaForms < 3.5.8.2 - Admin+ Stored Cross-Site Scripting

Severity: medium (CVSS 4.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-10-25 · updated 2026-06-17
Weakness: CWE-79

Description

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

Ninjaforms Contact Form: before 3.5.8.2 — fixed in 3.5.8.2

How to fix

Upgrade to a fixed version: Ninjaforms Contact Form 3.5.8.2. Check the vendor advisory for mitigations.

References

https://wpscan.com/vulnerability/e383fae6-e0da-4aba-bb62-adf51c01bf8d
https://wpscan.com/vulnerability/e383fae6-e0da-4aba-bb62-adf51c01bf8d

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