3.7

CVSS Score

3.1

-

CVSS Score

Basic Information

CVE ID

CVE-2021-3754

GHSA ID

GHSA-4vc8-pg5c-vg4x

EPSS Score

0.89136%

CWE

CWE-670

Published

6/12/2024

Updated

12/20/2024

KEV Status

Technology

Java

Basic Information

CVE ID

GHSA ID

EPSS Score

CWE

Published

Updated

KEV Status

Technology

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CVE-2021-3754

CVE-2021-3754: Keycloak's improper input validation allows using email as username

Keycloak allows the use of email as a username and doesn't check that an account with this email already exists. That could lead to the unability to reset/login with email for the user. This is caused by usernames being evaluated before emails.

(GitHub Advisory)

Miggo Vulnerability Database

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CVE-2021-3754

CVE-2021-3754:

3.7

CVSS Score

3.1

-

CVSS Score

Basic Information

CVE ID

CVE-2021-3754

GHSA ID

GHSA-4vc8-pg5c-vg4x

EPSS Score

0.89136%

CWE

CWE-670

Published

6/12/2024

Updated

12/20/2024

KEV Status

Technology

Java

Basic Information

CVE ID

GHSA ID

EPSS Score

CWE

Published

Updated

KEV Status

Technology

Technical Details

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
org.keycloak:keycloak-services	maven	< 24.0.1	24.0.1

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability stemmed from:

UsersResource.createUser's original implementation (removed in patch) only checked username/email existence in isolation without cross-validation between fields
Validators lacked bidirectional checks between username and email fields
The CWE-670 (incorrect control flow) manifests in username validation occurring before email checks, allowing email-as-username registration before email uniqueness verification
Patch adds cross-checks in validators and removes redundant checks from UsersResource, confirming these were the missing protections

Vulnerable functions

Only Mi**o us*rs **n s** t*is s**tion

WAF Protection Rules

WAF Rule

W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.

Reasoning

*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.

3.7

-

Basic Information

Basic Information

Concerned about an active attack path?

CVE-2021-3754: Keycloak's improper input validation allows using email as username

CVE-2021-3754:

3.7

-

Basic Information

Basic Information

Technical Details

Technical Details

Vulnerability IntelligenceMiggo AI

Root Cause Analysis

Vulnerable functions

WAF Protection Rules

WAF Rule

Reasoning

Vulnerability IntelligenceMiggo AI

3.7

3.7

CVE-2021-3754: Keycloak's improper input validation allows using email as username

Basic Information

Basic Information

Technical Details

Vulnerability IntelligenceMiggo AI

Root Cause Analysis

Vulnerable functions

WAF Protection Rules

WAF Rule

Reasoning

Vulnerability Intelligence
Miggo AI

Vulnerability Intelligence
Miggo AI

Vulnerability Intelligence
Miggo AI