Keycloak: Application-Level DoS via Scope Processing
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.
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describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-4634US | — | — | ||
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… | ||||
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references
External citations — patches, advisories, analysis.
- https://access.redhat.com/errata/RHSA-2026:6475WEB
- https://access.redhat.com/errata/RHSA-2026:6476WEB
- https://access.redhat.com/errata/RHSA-2026:6477WEB
- https://access.redhat.com/errata/RHSA-2026:6478WEB
- https://access.redhat.com/security/cve/CVE-2026-4634WEB
- https://bugzilla.redhat.com/show_bug.cgi?id=2450250WEB
- https://github.com/keycloak/keycloakPACKAGE
- https://github.com/keycloak/keycloak/commit/b455ee4f28abb6f2120aff72fd179589cc5267a0WEB
scry
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