CVE-2026-16443: Signature Bypass (CVSS 7.4)

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.

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CVSS v3.1 Score

7.4

HIGH

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

Weakness Type (CWE)

CWE-347 CWE-347

References

Other References

https://access.redhat.com/errata/RHSA-2026:50846 https://access.redhat.com/errata/RHSA-2026:50847 https://access.redhat.com/errata/RHSA-2026:50848 https://access.redhat.com/errata/RHSA-2026:50849 https://access.redhat.com/security/cve/CVE-2026-16443 https://bugzilla.redhat.com/show_bug.cgi?id=2503139

Frequently Asked Questions

What is CVE-2026-16443? +

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. It has a CVSS v3.1 base score of 7.4 (HIGH).

How severe is CVE-2026-16443? +

CVE-2026-16443 has a CVSS v3.1 score of 7.4 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

How do I check if I'm vulnerable to CVE-2026-16443? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-16443