---
id: CVE-2026-16093
title: >-
  Keycloak provides a mechanism called Client Policies to enforce security
  requirements on clients, such as requiring them to use signed JWTs for
  authentication
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 wit…
severity: medium
cvss: 5.4
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N'
cwe:
  - CWE-807
vendor: redhat
product: build_of_keycloak
affected:
  - build_of_keycloak
  - data_grid = 8.0
  - jboss_enterprise_application_platform_expansion_pack
  - single_sign-on = 7.0
patched:
  - build_of_keycloak 26.6.7
published: '2026-07-17'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T19:17:07.373'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-16093'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:68277'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:68278'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-16093'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2501729'
    label: secalert@redhat.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-16093.json
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-16093'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-16093'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00393
epssPercentile: 0.33347
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-07-21T01:45:36.335145Z'
ingestedAt: '2026-08-09T15:33:36.435Z'
---

## Overview

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.

## Affected

- `build_of_keycloak`
- `data_grid = 8.0`
- `jboss_enterprise_application_platform_expansion_pack`
- `single_sign-on = 7.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **RHSA-2026:68278** · Red Hat · fixed in: Red Hat build of Keycloak 26.6.7 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68278)
- **Red Hat VEX** · Moderate · affected: Red Hat Data Grid 8, Red Hat JBoss Enterprise Application Platform Expansion Pack, Red Hat Single Sign-On 7 · no fix planned: Red Hat Data Grid 8, Red Hat JBoss Enterprise Application Platform Expansion Pack, Red Hat Single Sign-On 7 · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-16093.json)
- **RHSA-2026:68277** · Red Hat · fixed in: Red Hat build of Keycloak 26.6 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68277)