Vulnerability-Lookup

CVE-2026-16093 (GCVE-0-2026-16093)

Vulnerability from cvelistv5 – Published: 2026-07-17 16:42 – Updated: 2026-09-16 18:34

Title

Keycloak-services: keycloak-services: required signed-jwt assertion policy can be bypassed with unsigned assertion headers

Summary

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.

Severity

5.4 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-21 01:45 UTC

CWE

CWE-807 - Reliance on Untrusted Inputs in a Security Decision

Assigner

redhat CNA under the redhat root

CNA scorecard B 82/100 over 1063 records in the last 180 days details

References

4 references

URL	Tags
https://access.redhat.com/errata/RHSA-2026:68277	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:68278	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-16093	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2501729	issue-trackingx_refsource_REDHAT

Impacted products

6 products

Vendor	Product	Version
Red Hat	Red Hat build of Keycloak 26.6	Unaffected: 26.6.7-3 , < * (rpm) cpe:/a:redhat:build_keycloak:26.6::el9
Red Hat	Red Hat build of Keycloak 26.6	Unaffected: 26.6-20 , < * (rpm) cpe:/a:redhat:build_keycloak:26.6::el9
Red Hat	Red Hat build of Keycloak 26.6.7	cpe:/a:redhat:build_keycloak:26.6::el9
Red Hat	Red Hat Data Grid 8	cpe:/a:redhat:jboss_data_grid:8
Red Hat	Red Hat JBoss Enterprise Application Platform Expansion Pack	cpe:/a:redhat:jbosseapxp
Red Hat	Red Hat Single Sign-On 7	cpe:/a:redhat:red_hat_single_sign_on:7

Date Public

2026-07-16 17:01

Credits

Red Hat would like to thank Paul Bottinelli (Trail of Bits in collaboration with OpenAI) for reporting this issue.

Show details on NVD website

JSON

To clipboard

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bit-keycloak-2026-16093

Vulnerability from bitnami_vulndb

Published

2026-08-31 14:36

Modified

2026-09-17 12:08

Summary

Keycloak-services: keycloak-services: required signed-jwt assertion policy can be bypassed with unsigned assertion headers

Details

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "keycloak",
        "purl": "pkg:bitnami/keycloak"
      },
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            {
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        }
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          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
          "type": "CVSS_V3"
        }
      ]
    }
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    ],
    "severity": "Medium"
  },
  "details": "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.",
  "id": "BIT-keycloak-2026-16093",
  "modified": "2026-09-17T12:08:03.261Z",
  "published": "2026-08-31T14:36:55.423Z",
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  "summary": "Keycloak-services: keycloak-services: required signed-jwt assertion policy can be bypassed with unsigned assertion headers"
}

CLEANSTART-2026-AH74122 (CVE-2026-16093)

Vulnerability from cleanstart – Published: 2026-09-19 00:41 – Updated: 2026-10-08 14:25 – Source website

Summary

Keycloak provides a mechanism called Client Policies to enforce security requirements on clients, such as requiring them to use signed JWTs for authentication

Details

Security vulnerability affects the keycloak package. Keycloak provides a mechanism called Client Policies to enforce security requirements on clients, such as requiring them to use signed JWTs for authentication.

Severity

9.8 (Critical)


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

References

URL

Type

	https://github.com/cleanstart-dev/cleanstart-secu…	ADVISORY
	https://osv.dev/vulnerability/CVE-2026-16093	WEB
	https://nvd.nist.gov/vuln/detail/CVE-2026-16093	WEB

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "CleanStart",
        "name": "keycloak",
        "purl": "pkg:apk/cleanstart/keycloak?arch=noarch"
      },
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  ]
}

FKIE_CVE-2026-16093

Vulnerability from fkie_nvd - Published: 2026-07-17 17:17 - Updated: 2026-09-16 19:17

Severity

5.4 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Summary

References

URL	Tags
secalert@redhat.com	https://access.redhat.com/errata/RHSA-2026:68277
secalert@redhat.com	https://access.redhat.com/errata/RHSA-2026:68278
secalert@redhat.com	https://access.redhat.com/security/cve/CVE-2026-16093	Vendor Advisory
secalert@redhat.com	https://bugzilla.redhat.com/show_bug.cgi?id=2501729	Issue Tracking, Vendor Advisory

Impacted products

Vendor	Product	Version
redhat	build_of_keycloak	-
redhat	data_grid	8.0
redhat	jboss_enterprise_application_platform_expansion_pack	-
redhat	single_sign-on	7.0

JSON

To clipboard

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GHSA-JMHG-9C54-P575

Vulnerability from github – Published: 2026-07-17 18:31 – Updated: 2026-09-16 18:31

Details

Severity

5.4 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-16093"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-807"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-17T17:17:14Z",
    "severity": "MODERATE"
  },
  "details": "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.",
  "id": "GHSA-jmhg-9c54-p575",
  "modified": "2026-09-16T18:31:18Z",
  "published": "2026-07-17T18:31:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-16093"
    },
    {
      "type": "WEB",
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    },
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    }
  ]
}

RHSA-2026:68277

Vulnerability from csaf_redhat - Published: 2026-09-16 15:46 - Updated: 2026-10-27 05:13

Summary

Red Hat Security Advisory: Red Hat build of Keycloak 26.6.7 Images Security Update

Severity

Important

Scope

28 vulnerabilities in this advisory, including CVE-2026-16093.

CVE-2026-16093

5.4 (Medium)


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

Fixed: 9 products

https://access.redhat.com/errata/RHSA-2026:68277

Open the full advisory

RHSA-2026:68278

Vulnerability from csaf_redhat - Published: 2026-09-16 15:45 - Updated: 2026-10-27 05:13

Summary

Red Hat Security Advisory: Red Hat build of Keycloak 26.6.7 Security Update

Severity

Important

Scope

28 vulnerabilities in this advisory, including CVE-2026-16093.

CVE-2026-16093

5.4 (Medium)


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

Fixed: 1 product

https://access.redhat.com/errata/RHSA-2026:68278

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-16093 (GCVE-0-2026-16093)

bit-keycloak-2026-16093

Vulnerability from bitnami_vulndb

CLEANSTART-2026-AH74122 (CVE-2026-16093)

FKIE_CVE-2026-16093

GHSA-JMHG-9C54-P575

RHSA-2026:68277

RHSA-2026:68278

Tags

Sightings

Nomenclature

Vulnerability timeline

Related by attack behaviour