CVE-2026-1180
Description
A flaw was identified in Keycloak’s OpenID Connect Dynamic Client Registration feature when clients authenticate using private_key_jwt. The issue allows a client to specify an arbitrary jwks_uri, which Keycloak then retrieves without validating the destination. This enables attackers to coerce the Keycloak server into making HTTP requests to internal or restricted network resources. As a result, attackers can probe internal services and cloud metadata endpoints, creating an information disclosure and reconnaissance risk.
Statement
This vulnerability is rated Moderate for Red Hat. The flaw in Keycloak's OIDC Dynamic Client Registration allows an attacker to force the Keycloak server to make requests to internal network resources via a crafted jwks_uri parameter. This can lead to information disclosure and internal network reconnaissance, particularly in configurations that permit anonymous or token-based client registration.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.8 | N/A | 5.8 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Changed | N/A | Changed |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Integrity
Technical Impact: Execute Unauthorized Code or Commands
Access Control
Technical Impact: Bypass Protection Mechanism
By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.
Acknowledgements
Red Hat would like to thank Lucas Montes (Nirox) for reporting this issue.
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