sales@hackhalt.com
Free Download

Home / Threats / CVE-2021-24239

Pie Register - Cross-Site Scripting (XSS) (CVE-2021-24239)

CVE-2021-24239

Vulnerability CVE-2021-24239 PLUGIN pie-register MEDIUM

The Pie Register – User Registration Forms. Invitation based registrations, Custom Login, Payments WordPress plugin before 3.7.0.1 does not sanitise the invitaion_code GET parameter when outputting it in the Activation Code page, leading to a reflected Cross-Site Scripting issue.

CVE-2021-24239

MEDIUM CVSS 6.1 Published 2021-04-22 Updated 2026-06-17
AI Risk Moderate (53/100) Active Exploit: No strong signal Published Exploit: No public exploit references Priority: P4 Planned
Severity Band MEDIUM
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Affected Components 1
Reference Links 2
AI Risk Engine Moderate (53/100)
Exploitability Medium
Active Exploitation No strong signal
Published Exploit Status No public exploit references

Threat Timeline

  1. 2021-04-22 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 163 days ago

AI enriched 163 days ago (2026-04-11 17:43 UTC)

Technical Summary

The Pie Register – User Registration Forms. Invitation based registrations, Custom Login, Payments WordPress plugin before 3.7.0.1 does not sanitise the invitaion_code GET parameter when outputting it in the Activation Code page, leading to a reflected Cross-Site Scripting issue.

Potential Impact

Severity is MEDIUM (CVSS 6.1). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.

Exploitability Assessment

Exploitability is assessed as Medium 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 53/100 (Moderate, Medium) with priority P4 Planned. Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.

Affected Products

Pie Register PLUGIN · pie-register Affected: < 3.7.0.1 Fixed in: 3.7.0.1

Related Vulnerabilities

Browse All Threats

Newest linked vulnerabilities to keep visitors exploring adjacent CVE coverage.

Pie Register - Security Vulnerability (CVE-2026-10530) CVE-2026-10530 Published 2026-06-22 Pie Register - Broken Access Control (CVE-2026-3571) CVE-2026-3571 Published 2026-04-04 Pie Register - Broken Access Control (CVE-2026-24577) CVE-2026-24577 Published 2026-01-23 Pie Register - Remote Code Execution (CVE-2025-34077) CVE-2025-34077 Published 2025-07-09 Pie Register - Information Disclosure (CVE-2024-13818) CVE-2024-13818 Published 2025-02-21 Pie Register - Broken Access Control (CVE-2024-6069) CVE-2024-6069 Published 2024-07-09

References

What to do about this

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

Fix it

Update Pie Register to 3.7.0.1 or later.

That is the complete fix. Everything below is what protects you in the meantime.

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.

Compare Hack Halt plans Start free

Not sure if you are affected?

Scan your site to see whether it runs Pie Register, 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.

Scan my site free See what Hack Halt does

Am I affected by this vulnerability?

You are affected if your site runs Pie Register. Versions below 3.7.0.1 are vulnerable; that release and later are not.

How do I fix it?

Update Pie Register to version 3.7.0.1 or later. That is the complete fix. 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 Scripting (XSS) flaw. An attacker who exploits it can run script in a visitor's browser, stealing sessions or planting an administrator account.

WordPress security that blocks attacks before they land.

sales@hackhalt.com

Product

Resources

Company

© Hack Halt Inc. All rights reserved.