๐Ÿ” CVE Alert

CVE-2026-18211

MEDIUM 4.2

Keycloak-services: keycloak-services: secure-client-uris policy bypass via localhost-prefixed domains

CVSS Score
4.2
EPSS Score
0.0%
EPSS Percentile
0th

A flaw was found in the secure-client-uris client policy executor within Keycloak core services. This component is responsible for enforcing security requirements on client configurations, such as requiring encrypted connections for redirect URIs. Due to an improper check that only looks at the start of a web address rather than properly verifying the host, an attacker can bypass these security restrictions by using a specially crafted domain name. This could allow an attacker to intercept sensitive authentication codes over unencrypted connections.

CWE CWE-20
Vendor red hat
Product red hat build of keycloak
Published Jul 31, 2026
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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

Affected Versions

Red Hat / Red Hat Build of Keycloak
All versions affected
Red Hat / Red Hat Build of Keycloak
All versions affected
Red Hat / Red Hat Build of Keycloak
All versions affected
Red Hat / Red Hat Data Grid 8
All versions affected
Red Hat / Red Hat JBoss Enterprise Application Platform Expansion Pack
All versions affected
Red Hat / Red Hat Single Sign-On 7
All versions affected

References

NVD โ†— CVE.org โ†— EPSS Data โ†—
access.redhat.com: https://access.redhat.com/security/cve/CVE-2026-18211 bugzilla.redhat.com: https://bugzilla.redhat.com/show_bug.cgi?id=2508306

Credits

Red Hat would like to thank Paul Bottinelli (Trail of Bits) for reporting this issue.