CVE-2021-3827

Name: CVE-2021-3827
Creator: NVD / NIST
Published: 2022-08-23T16:15:10.03+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.8/10EPSS 0.87%

Last modified Jun 17, 2026

CVE-2021-3827 is a medium-severity vulnerability rated 6.8/10 on the CVSS scale. A flaw was found in keycloak, where the default ECP binding flow allows other authentication flows to be bypassed. By exploiting this behavior, an attacker can bypass the MFA authentication by sending a SOAP request with an AuthnRequest and Authorization header with the user's credentials. EPSS estimates a 0.87% chance of exploitation in the next 30 days.

Description

A flaw was found in keycloak, where the default ECP binding flow allows other authentication flows to be bypassed. By exploiting this behavior, an attacker can bypass the MFA authentication by sending a SOAP request with an AuthnRequest and Authorization header with the user's credentials. The highest threat from this vulnerability is to confidentiality and integrity.

Metrics

CVSS 3.1

6.8/10

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

EPSS Probability

0.87%

54.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Redhat	Keycloak	< 18.0.0
Redhat	Single Sign-On	7.0
Redhat	Single Sign-On	7.5.0
Redhat	Openshift Container Platform	4.8
Redhat	Openshift Container Platform	4.9

References

https://access.redhat.com/security/cve/CVE-2021-3827Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2007512Issue Tracking, Vendor Advisory
https://github.com/keycloak/keycloak/commit/44000caaf5051d7f218d1ad79573bd3d175cad0dPatch, Third Party Advisory
https://github.com/keycloak/keycloak/security/advisories/GHSA-4pc7-vqv5-5r3vThird Party Advisory
https://access.redhat.com/security/cve/CVE-2021-3827Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2007512Issue Tracking, Vendor Advisory
https://github.com/keycloak/keycloak/commit/44000caaf5051d7f218d1ad79573bd3d175cad0dPatch, Third Party Advisory
https://github.com/keycloak/keycloak/security/advisories/GHSA-4pc7-vqv5-5r3vThird Party Advisory

Timeline

Published: Aug 23, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3827?

How severe is CVE-2021-3827?

CVE-2021-3827 has a CVSS score of 6.8/10 (MEDIUM severity). The EPSS model estimates a 0.87% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3827?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3827?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST