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Vulnerability record · CVE-2026-16442 · published 5 August 2026

CVE-2026-16442: Redhat build of keycloak origin validation error vulnerability

Redhat · Build Of Keycloak

A flaw was found in the SAML broker component of Keycloak, which is used to manage identity federation and user authentication. The issue occurs because the IdP-initiated Single Sign-On endpoint fails to check if a provider is restricted to account linking only. This allows an attacker with control over a linked upstream identity to bypass login restrictions and gain full access to a local user account.

9.8 CVSS 3.1 Critical EPSS 0.31% · top 78.2% CWE-346 · Origin validation error
9.8CVSS 3.1 base score
0.31%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
6References
10 Aug 2026Last modified by NVD

Description

A flaw was found in the SAML broker component of Keycloak, which is used to manage identity federation and user authentication. The issue occurs because the IdP-initiated Single Sign-On endpoint fails to check if a provider is restricted to account linking only. This allows an attacker with control over a linked upstream identity to bypass login restrictions and gain full access to a local user account.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://access.redhat.com/errata/RHSA-2026:50846 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:50847 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:50848 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:50849 Vendor Advisory
https://access.redhat.com/security/cve/CVE-2026-16442 Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2503138 Issue TrackingVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.1CVE-2026-16443Redhat build of keycloak improper verification of cryptographic signature vulnerabilityA flaw was found in the SAML metadata import functionality of the keycloak-services component, which is the core engine for identity brokering in Red…EPSS 0.26%8.8CVE-2026-15572Redhat build of keycloak type confusion vulnerabilityA flaw was found in Keycloak's Dynamic Client Registration (DCR) security policy management. The "Allowed Protocol Mapper Types" policy, which restri…EPSS 0.65%8.8CVE-2026-9704Redhat build of keycloak vulnerabilityA flaw was found in Keycloak. An authenticated user with low privileges can exploit this vulnerability by sending an oversized subject_token JSON Web…EPSS 0.59%8.8CVE-2026-3047Redhat build of keycloak vulnerabilityA flaw was found in org.keycloak.broker.saml. When a disabled Security Assertion Markup Language (SAML) client is configured as an Identity Provider …EPSS 0.86%8.8CVE-2023-6787Redhat build of keycloak improper authentication vulnerabilityA flaw was found in Keycloak that occurs from an error in the re-authentication mechanism within org.keycloak.authentication. This flaw allows hijack…EPSS 0.74%8.1CVE-2026-18967Redhat build of keycloak authentication bypass by capture-replay vulnerabilityA flaw was found in the SAML broker component of Keycloak, an identity and access management solution. When configured as a SAML broker using the IdP…EPSS 0.23%8.1CVE-2026-16102Redhat build of keycloak improper access control vulnerabilityA flaw was found in the Dynamic Client Registration (DCR) component of Keycloak, an identity and access management solution. The default DCR policy f…EPSS 0.46%8.1CVE-2026-15573Redhat build of keycloak vulnerabilityA flaw was found in Keycloak's Authorization Services. The component responsible for matching request paths to security policies (PathMatcher) does n…EPSS 0.46%

Source: NIST National Vulnerability Database (record CVE-2026-16442), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.