CVE-2026-93998

Keycloak-core: keycloak-core: saml adapter does not bind signed assertions to the configured identity provider issuer

Published Nov 5, 2026 CVSS 3.1 · 7.4 High EPSS < 1% KEV · Not listed
Description
A flaw was found in the SAML adapter component of Keycloak, which is used to secure applications with SAML-based authentication. The adapter fails to verify that the issuer of a signed SAML assertion matches the expected identity provider configured for the application. If multiple identity providers share the same trusted signing key, an attacker who controls one of those providers can create a validly signed assertion to log into the application as any user, potentially gaining full administrative control.

Remediation

Vendor Workaround

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. --- CME Mitigation Guidance (2026-11-06) --- Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure. The highest-value action is to enforce strict verification of the SAML assertion Issuer attribute against the configured identity provider entity ID in the Keycloak SAML adapter: upgrade to Red Hat build of Keycloak 26.4.17, 26.6.8 (or the corresponding fixed Red Hat builds), which verify that the Issuer attribute in the received SAML response and assertion strictly matches the configured identity provider entity ID, closing all 2 injection vectors (cross-tenant SAML assertion injection, shared-key sibling issuer assertion forging). Until patched, this is a concern on Applications secured using the Keycloak SAML adapter where signing keys are shared across multiple identity providers or tenants, so Ensure signing keys are strictly isolated per identity provider and never shared across multiple issuers or tenants. These controls limit blast radius and contain exploitation, but they do not fix the underlying missing SAML issuer validation defect — apply the upstream patch to fully remediate. Highest-impact CME: CME-1315 Allowlist-Preferred Input Validation (Deny-by-Default Filtering) (high)

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
CPEs cpe:/a:redhat:build_keycloak: cpe:/a:redhat:build_keycloak:26.4::el9
cpe:/a:redhat:build_keycloak:26.6::el9
References
Type Values Removed Values Added
Description A flaw was found in the SAML adapter component of Keycloak, which is used to secure applications with SAML-based authentication. The adapter fails to verify that the issuer of a signed SAML assertion matches the expected identity provider configured for the application. If multiple identity providers share the same trusted signing key, an attacker who controls one of those providers can create a validly signed assertion to log into the application as any user, potentially gaining full administrative control.
Title Keycloak-core: keycloak-core: saml adapter does not bind signed assertions to the configured identity provider issuer
First Time appeared Redhat
Redhat amq Broker
Redhat build Keycloak
Redhat jboss Enterprise Application Platform
Redhat jboss Fuse
Redhat jbosseapxp
Redhat red Hat Single Sign On
Redhat satellite
Weaknesses CWE-347
CPEs cpe:/a:redhat:amq_broker:7
cpe:/a:redhat:build_keycloak:
cpe:/a:redhat:jboss_enterprise_application_platform:7
cpe:/a:redhat:jboss_enterprise_application_platform:8
cpe:/a:redhat:jboss_fuse:7
cpe:/a:redhat:jbosseapxp
cpe:/a:redhat:red_hat_single_sign_on:7
cpe:/a:redhat:satellite:6
Vendors & Products Redhat
Redhat amq Broker
Redhat build Keycloak
Redhat jboss Enterprise Application Platform
Redhat jboss Fuse
Redhat jbosseapxp
Redhat red Hat Single Sign On
Redhat satellite
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Nov 6, 2026, 7:44 PM
Reserved
Sep 19, 2026, 1:55 PM
Status
Awaiting Analysis
Published
Nov 5, 2026, 6:17 PM
Modified
Nov 6, 2026, 5:20 PM
Severity
Important
Public date
Nov 5, 2026, 12:00 AM