Description
A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to impersonate any federated user linked to the affected Identity Provider, leading to unauthorized access and potential privilege escalation.
Published: 2026-06-25
Score: 8.1 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Fri, 26 Jun 2026 14:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Fri, 26 Jun 2026 10:45:00 +0000

Type Values Removed Values Added
First Time appeared Redhat build Of Keycloak
Redhat data Grid
Redhat jboss Enterprise Application Platform Expansion Pack
Vendors & Products Redhat build Of Keycloak
Redhat data Grid
Redhat jboss Enterprise Application Platform Expansion Pack

Thu, 25 Jun 2026 21:30:00 +0000

Type Values Removed Values Added
Description A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to impersonate any federated user linked to the affected Identity Provider, leading to unauthorized access and potential privilege escalation.
Title Org.keycloak:keycloak-services: keycloak: authentication bypass via jwt algorithm confusion
First Time appeared Redhat
Redhat build Keycloak
Redhat jboss Data Grid
Redhat jbosseapxp
Redhat red Hat Single Sign On
Weaknesses CWE-347
CPEs cpe:/a:redhat:build_keycloak:
cpe:/a:redhat:build_keycloak:26.6::el9
cpe:/a:redhat:jboss_data_grid:8
cpe:/a:redhat:jbosseapxp
cpe:/a:redhat:red_hat_single_sign_on:7
Vendors & Products Redhat
Redhat build Keycloak
Redhat jboss Data Grid
Redhat jbosseapxp
Redhat red Hat Single Sign On
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N'}


Subscriptions

Redhat Build Keycloak Build Of Keycloak Data Grid Jboss Data Grid Jboss Enterprise Application Platform Expansion Pack Jbosseapxp Red Hat Single Sign On
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-06-26T13:03:54.683Z

Reserved: 2026-06-09T14:06:04.695Z

Link: CVE-2026-11800

cve-icon Vulnrichment

Updated: 2026-06-26T13:03:50.563Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-26T09:36:15Z

Weaknesses