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
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.011 (64.1th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 64.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: -0.000
Affected products
- Red Hat Enterprise Linux — versions 7.0, 8.0
- Red Hat Keycloak
- Red Hat Openshift Container Platform — versions 4.8, 4.9
- Red Hat Single Sign-On — versions 7.0, 7.5.0
- Keycloak — versions Fixed in v18.0.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/keycloak/keycloak/security/advisories/GHSA-4pc7-vqv5-5r3v (Third Party Advisory)
- github.com/keycloak/keycloak/commit/44000caaf5051d7f218d1ad79573bd3d175cad0d (Patch, Third Party Advisory)
- bugzilla.redhat.com/show_bug.cgi (Issue Tracking, Vendor Advisory)
- access.redhat.com/security/cve/CVE-2021-3827 (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.