Strategic Overview
- Status
- Patched in 3.7.1.6
- Affected Version
< 3.7.1.6- CVSS
- 9.8Critical
- Weakness type
- CWE-89 · Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')
- CVE
CVE-2021-24731
At a glance
CVE-2021-24731 is a critical-severity Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection') vulnerability in the Pie Register WordPress plugin, affecting versions < 3.7.1.6. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 3.7.1.6; sites on affected versions should update now. Disclosed October 2021, reported by AyeCode Ltd.
Vulnerability Overview
The Registration Forms – User profile, Content Restriction, Spam Protection, Payment Gateways, Invitation Codes WordPress plugin before 3.7.1.6 does not properly escape user data before using it in a SQL statement in the wp-json/pie/v1/login REST API endpoint, leading to an SQL injection.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.
CWE-89: Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')
Reaching this weakness in Pie Register < 3.7.1.6 takes no account at all. SQL injection happens when request data is concatenated into a query instead of being bound as a parameter, letting an attacker change the structure of the statement rather than just its values.
A working injection can read any table the database user can see, which on a WordPress install means user records, password hashes and session or API secrets stored in options. For Pie Register the fix is 3.7.1.6: builds < 3.7.1.6 are affected, anything from 3.7.1.6 onward is not.
Remediation
Update to version 3.7.1.6, or a newer patched version
How does WordSec protect against this?
Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Pie Register 3.7.1.6 closes this, and updating the plugin is the step that ends it.
- Firewall
- Login Security
- Alerts
External References
Related records
Same weakness class
Other vulnerabilities in Pie Register – User Registration, Profiles & Content Restriction
- 9.8CVE-2024-27957: Pie Register <= 3.8.3.2 Arbitrary File Upload
CVE-2024-27957 - 9.8CVE-2025-34077: Pie Register <= 3.7.1.4 Authentication Bypass
CVE-2025-34077 - 9.8Registration Forms Authentication Bypass
- 8.8CVE-2024-6069: Pie Register - Basic Authenticated (Subscriber+)
CVE-2024-6069 - 8.1CVE-2021-24647: Pie Register <= 3.7.1.5 Authentication Bypass
CVE-2021-24647 - 7.3CVE-2014-8802: Pie Register <= 2.0.13 Missing Authorization
CVE-2014-8802 - 7.1Pie Register < 3.0.18 Cross-Site Scripting
- 7.1Pie Register < 2.0.15 Cross-Site Scripting
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