Keycloak Denial of Service (DoS) Vulnerability via JWT Token Cache
A flaw was found in Keycloak. When the configuration uses JWT tokens for authentication, the tokens are cached until expiration. If a client uses JWT tokens with an excessively long expiration time, for example, 24 or 48 hours, the cache can grow indefinitely, leading to an OutOfMemoryError. This issue could result in a denial of service condition, preventing legitimate users from accessing the system.
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describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2025-2559US | — | — | ||
A flaw was found in Keycloak. When the configuration uses JWT tokens for authentication, the tokens are cached until expiration. If a client uses JWT tokens with an excessively lon… | ||||
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references
External citations — patches, advisories, analysis.
- https://access.redhat.com/errata/RHSA-2025:4335WEB
- https://access.redhat.com/errata/RHSA-2025:4336WEB
- https://access.redhat.com/security/cve/CVE-2025-2559WEB
- https://bugzilla.redhat.com/show_bug.cgi?id=2353868WEB
- https://github.com/keycloak/keycloakPACKAGE
- https://nvd.nist.gov/vuln/detail/CVE-2025-2559ADVISORY
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