CVE-2026-16443: Keycloak-services: keycloak-services: saml broker metadata import disables response signature validation

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-05 · updated 2026-08-10
Weakness: CWE-347

Description

A flaw was found in the SAML metadata import functionality of the keycloak-services component, which is the core engine for identity brokering in Red Hat Build of Keycloak. When importing identity provider metadata that lacks specific usage attributes for keys, the system incorrectly disables signature validation for SAML responses even if a signing certificate is provided. This issue allows an unauthenticated attacker to forge a SAML response and gain unauthorized access to a user account by knowing their external identifier.

Affected products

Red Hat build of Keycloak 26.4: from 26.4 before 26.4.14; from 26.6 before 26.6.5 — fixed in 26.4.14, 26.6.5

How to fix

Upgrade to a fixed version: Red Hat build of Keycloak 26.4 26.4.14, 26.6.5. Check the vendor advisory for mitigations.

References

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