A denial-of-service vulnerability exists in UAA's private_key_jwt client-authentication mechanism. When UAA retrieves a remote JWKS URI, it caches the response. Invalid authentication attempts can trigger full deserialization of this cached data. An attacker with prerequisites (write access to clients or a compromised endpoint) can send anonymous requests that force repeated parsing of large cached objects, causing excessive CPU usage and potential Java heap exhaustion via OutOfMemoryError, resulting in service unavailability.
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