CVE-2026-117688 in Keycloak
Summary
by MITRE • 10/29/2026
A flaw was found in the client registration component of Keycloak, an open-source identity and access management solution. When a vault provider is used to store sensitive information, an authenticated client owner can use a specially crafted reference to trick the system into revealing secrets. By updating a client secret to point to a vault entry and then requesting the client configuration, the owner can see the secret value in plain text. This could lead to the exposure of sensitive credentials that the user should not be able to access.
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Analysis
by VulDB Data Team • 10/29/2026
The vulnerability identified within Keycloak represents a critical failure in the separation of duties regarding credential management and retrieval mechanisms. Specifically, this flaw resides in the client registration component, which is responsible for handling the lifecycle and configuration details of OAuth2 or OpenID Connect clients. In enterprise environments utilizing vault providers such as HashiCorp Vault, CyberArk, or AWS Secrets Manager to store sensitive data like API keys and passwords, it is imperative that these secrets remain opaque during routine administrative operations. The architecture assumes that while a client owner may have permission to manage the reference pointer for their secret, they should not possess the ability to resolve or view the actual plaintext value stored within the external vault system. This assumption was violated due to an improper implementation of access controls and data handling logic in the API endpoints responsible for retrieving client configurations.
The technical root cause involves a lack of proper validation when resolving references to vault entries during the retrieval process. When an authenticated user with ownership privileges over a specific client attempts to update that client's secret configuration, they can set the value to point directly to a resource identifier within the connected vault provider rather than entering plaintext data. Subsequently, when this same user requests the full configuration details for their client through standard API calls or administrative interfaces, the system incorrectly resolves the vault reference and returns the actual decrypted secret in plain text as part of the response payload. This behavior effectively bypasses the intended security boundary that separates management permissions from decryption privileges, allowing any authenticated owner to escalate their access rights beyond what was originally granted by the identity provider administrators.
From an operational impact perspective, this vulnerability facilitates unauthorized disclosure of sensitive credentials, which can lead to severe consequences including account takeover, privilege escalation, and lateral movement within connected systems. If attackers compromise a legitimate client application or obtain valid authentication tokens for such clients, they can exploit this flaw to extract secrets that are meant to be protected by the vault infrastructure. This undermines the entire zero-trust model established by using external secret management solutions. The exposure of these credentials allows malicious actors to impersonate services, access restricted APIs, and potentially compromise downstream systems that trust the compromised client identity. In multi-tenant environments or large organizations where Keycloak serves as a central authentication hub, this flaw could result in widespread data breaches affecting multiple dependent applications simultaneously.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. The primary defense is to apply vendor-provided patches that correct the logic within the client registration component to ensure that vault references are never resolved into plaintext values during configuration retrieval operations. Administrators should verify their Keycloak version against known vulnerable releases and update accordingly until a permanent fix is available. In addition to patching, organizations should enforce strict least-privilege principles by reviewing which users or service accounts hold owner permissions over client configurations. It is advisable to restrict these privileges to dedicated administrative roles rather than application owners who do not require direct access to secret values. Furthermore, implementing audit logging for all attempts to retrieve client secrets can help detect exploitation activities in real time. Security teams should also consider integrating additional monitoring rules that flag unusual patterns of configuration changes followed immediately by retrieval requests, which may indicate active probing or exploitation of this vulnerability.