Keycloak provides a mechanism called Client Policies to enforce security requirements on clients, such as requiring them to use signed JWTs for authentication. A flaw was discovered where this enforcement can be bypassed. An attacker with valid client credentials can provide a fake, unsigned assertion header that tricks the system into thinking the policy requirements have been met. This allows the attacker to authenticate using simpler methods like a client secret even when the administrator has mandated more secure, signed assertions.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions |
|---|---|---|---|
| Red Hat | Red Hat Build of Keycloak | affected | — |
| Red Hat | Red Hat Build of Keycloak | affected | — |
| Red Hat | Red Hat Build of Keycloak | affected | — |
| Red Hat | Red Hat Data Grid 8 | affected | — |
| Red Hat | Red Hat JBoss Enterprise Application Platform Expansion Pack | affected | — |
| Red Hat | Red Hat Single Sign-On 7 | affected | — |
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Solution
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Workaround
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References
History
Fri, 17 Jul 2026 16:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Keycloak provides a mechanism called Client Policies to enforce security requirements on clients, such as requiring them to use signed JWTs for authentication. A flaw was discovered where this enforcement can be bypassed. An attacker with valid client credentials can provide a fake, unsigned assertion header that tricks the system into thinking the policy requirements have been met. This allows the attacker to authenticate using simpler methods like a client secret even when the administrator has mandated more secure, signed assertions. | |
| Title | Keycloak-services: keycloak-services: required signed-jwt assertion policy can be bypassed with unsigned assertion headers | |
| First Time appeared |
Redhat
Redhat build Keycloak Redhat jboss Data Grid Redhat jbosseapxp Redhat red Hat Single Sign On |
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| Weaknesses | CWE-807 | |
| CPEs | cpe:/a:redhat:build_keycloak: cpe:/a:redhat:jboss_data_grid:8 cpe:/a:redhat:jbosseapxp cpe:/a:redhat:red_hat_single_sign_on:7 |
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| Vendors & Products |
Redhat
Redhat build Keycloak Redhat jboss Data Grid Redhat jbosseapxp Redhat red Hat Single Sign On |
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| References |
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| Metrics |
cvssV3_1
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Projects
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MITRE
Status: PUBLISHED
Assigner: redhat
Published:
Updated: 2026-07-17T16:42:52.407Z
Reserved: 2026-07-17T14:08:34.722Z
Link: CVE-2026-16093
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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Weaknesses