CVE-2026-4634: Excessive Platform Resource Consumption within a Loop in Red Hat Red Hat build of Keycloak 26.2
A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times, ultimately resulting in a Denial of Service (DoS) for the Keycloak server.
AI Analysis
Technical Summary
This vulnerability (CVE-2026-4634) in Red Hat build of Keycloak 26.2 allows an unauthenticated attacker to cause a Denial of Service by sending a POST request with an excessively long scope parameter to the OpenID Connect token endpoint. The flaw leads to excessive resource consumption due to processing within a loop, degrading service availability. The issue is tracked under CWE-1050 (Excessive Resource Consumption). Red Hat has published security advisories and released version 26.2.15 containing the fix.
Potential Impact
The vulnerability results in a Denial of Service (DoS) condition by exhausting platform resources and causing prolonged processing times when handling maliciously crafted requests. There is no impact on confidentiality or integrity reported. The service disruption affects availability of the Keycloak authentication server, potentially impacting dependent applications and services.
Mitigation Recommendations
Red Hat has released an official fix in Red Hat build of Keycloak version 26.2.15. Users should upgrade to version 26.2.15 or later to remediate this vulnerability. Before applying the update, back up existing installations, including applications, configuration files, and databases. No other mitigations or workarounds are specified in the vendor advisory.
CVE-2026-4634: Excessive Platform Resource Consumption within a Loop in Red Hat Red Hat build of Keycloak 26.2
Description
A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times, ultimately resulting in a Denial of Service (DoS) for the Keycloak server.
CVSS v3.1
Score 7.5high
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-4634) in Red Hat build of Keycloak 26.2 allows an unauthenticated attacker to cause a Denial of Service by sending a POST request with an excessively long scope parameter to the OpenID Connect token endpoint. The flaw leads to excessive resource consumption due to processing within a loop, degrading service availability. The issue is tracked under CWE-1050 (Excessive Resource Consumption). Red Hat has published security advisories and released version 26.2.15 containing the fix.
Potential Impact
The vulnerability results in a Denial of Service (DoS) condition by exhausting platform resources and causing prolonged processing times when handling maliciously crafted requests. There is no impact on confidentiality or integrity reported. The service disruption affects availability of the Keycloak authentication server, potentially impacting dependent applications and services.
Mitigation Recommendations
Red Hat has released an official fix in Red Hat build of Keycloak version 26.2.15. Users should upgrade to version 26.2.15 or later to remediate this vulnerability. Before applying the update, back up existing installations, including applications, configuration files, and databases. No other mitigations or workarounds are specified in the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- redhat
- Date Reserved
- 2026-03-23T08:41:40.650Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/errata/RHSA-2026:6475","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:6476","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:6477","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:6478","vendor":"Red Hat"},{"url":"https://access.redhat.com/security/cve/CVE-2026-4634","vendor":"Red Hat"}]
Threat ID: 69ce6a44e6bfc5ba1dd993af
Added to database: 04/02/2026, 13:08:20 UTC
Last enriched: 07/15/2026, 09:26:24 UTC
Last updated: 07/31/2026, 19:22:59 UTC
Views: 371
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