What’s Vulnerable › Vulnerabilities

CVE-2021-34648: Ninja Forms <= 3.5.7 Unprotected REST-API to Email Injection

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-09-22 · updated 2026-06-17
• Weakness: CWE-863

Description

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

• kstover Ninja Forms – The Contact Form Builder That Grows With You: through 3.5.7

References

• https://plugins.trac.wordpress.org/browser/ninja-forms/trunk/includes/Routes/Submissions.php?rev=2543837#L155
• https://www.wordfence.com/blog/2021/09/recently-patched-vulnerabilities-in-ninja-forms-plugin-affects-over-1-million-site-owners/
• https://plugins.trac.wordpress.org/browser/ninja-forms/trunk/includes/Routes/Submissions.php?rev=2543837#L155
• https://www.wordfence.com/blog/2021/09/recently-patched-vulnerabilities-in-ninja-forms-plugin-affects-over-1-million-site-owners/

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