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Easy Registration Forms - Cross-Site Request Forgery (CSRF) (CVE-2021-39353)

CVE-2021-39353

Vulnerability CVE-2021-39353 PLUGIN easy-registration-forms HIGH

The Easy Registration Forms WordPress plugin is vulnerable to Cross-Site Request Forgery due to missing nonce validation via the ajax_add_form function found in the ~/includes/class-form.php file which made it possible for attackers to inject arbitrary web scripts in versions up to, and including 2.1.1.

CVE-2021-39353

HIGH CVSS 8.8 Published 2021-11-19 Updated 2026-06-17
AI Risk High (78/100) Active Exploit: No strong signal Published Exploit: No public exploit references Priority: P2 Urgent
Severity Band HIGH
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Affected Components 1
Reference Links 2
AI Risk Engine High (78/100)
Exploitability High
Active Exploitation No strong signal
Published Exploit Status No public exploit references

Threat Timeline

  1. 2021-11-19 CVE published and first recorded in the threat feed.
  2. 2026-06-17 Record updated with latest vulnerability metadata.
  3. 2026-04-11 AI technical context refreshed for mitigation and impact guidance.
  4. Now Monitoring for follow-up changes, linked references, and new related CVEs.

AI Context

Machine-generated threat intelligence

AI Updated 173 days ago

AI enriched 173 days ago (2026-04-11 00:39 UTC)

Technical Summary

The Easy Registration Forms WordPress plugin is vulnerable to Cross-Site Request Forgery due to missing nonce validation via the ajax_add_form function found in the ~/includes/class-form.php file which made it possible for attackers to inject arbitrary web scripts in versions up to, and including 2.1.1.

Potential Impact

Severity is HIGH (CVSS 8.8). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.

Exploitability Assessment

Exploitability is assessed as High based on severity and technical exposure profile.

Primary risk drivers: severity and technical exposure profile

Mitigation Recommendations

Validate affected product versions, prioritize patching, and monitor references for vendor remediation guidance. If immediate patching is not possible, apply compensating controls and limit exposure of vulnerable surfaces.

Detection & Monitoring

Track authentication anomalies, unexpected file writes, and suspicious plugin API activity around affected components.

Business Impact Lens

AI risk score 78/100 (High, High) with priority P2 Urgent. Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.

Affected Products

Easy Registration Forms PLUGIN · easy-registration-forms Affected: <= 2.1.1 Fixed version not specified

References

What to do about this

Patch on your next cycle Worth fixing, but not ahead of other work.

Fix it

Update Easy Registration Forms to the latest available version.

Where the vendor has not published a fix yet, disable the plugin until they do.

Cannot update today? Request / payload inspection (WAF) in Hack Halt ProSecure blocks this class of attack before WordPress processes the request.

Inspect request parameters and bodies for injection, traversal and file-inclusion payloads, and refuse the request rather than logging it.

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Not sure if you are affected?

Scan your site to see whether it runs Easy Registration Forms, and at which version.

Free, no installation, no account. It reads what your site already publishes, then tells you which plugins carry known vulnerabilities and what to do about each one.

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Am I affected by this vulnerability?

You are affected if your site runs Easy Registration Forms.

How do I fix it?

Update Easy Registration Forms to the latest available version. Where the vendor has not yet published a fix, remove or disable the plugin until they do. Until you can update, Request / payload inspection (WAF) in Hack Halt ProSecure contains this class of attack at the request layer.

What can an attacker actually do?

This is a Cross-Site Request Forgery (CSRF) flaw. An attacker who exploits it can make a logged-in administrator perform an action just by visiting a page.

WordPress security that blocks attacks before they land.

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