Auth bypass in Red Hat Enterprise Linux
CVE-2021-3827
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.
Vulnerability class: Broken Authentication
EPSS: 0.009 (55.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N.
Affected products
- Redhat Enterprise_linux — versions 7.0, 8.0
- Redhat Keycloak
- Redhat Openshift_container_platform — versions 4.8, 4.9
- Redhat Single_sign-on — versions 7.0, 7.5.0
- N/a Keycloak — versions Fixed in v18.0.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- secalert@redhat.com (Third Party Advisory, x_refsource_MISC)
- secalert@redhat.com (Patch, Third Party Advisory, x_refsource_MISC)
- secalert@redhat.com (x_refsource_MISC, Issue Tracking, Vendor Advisory)
- secalert@redhat.com (x_refsource_MISC, Vendor Advisory)
Frequently asked questions
- What is CVE-2021-3827?
- CVE-2021-3827 is a medium-severity vulnerability in Red Hat Enterprise Linux, classified under Improper Authentication. CVSS score: 6.8/10. Published 2022-08-23.
- How severe is CVE-2021-3827?
- Medium severity. CVSS v3 base score is 6.8 out of 10.
- Is CVE-2021-3827 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.