Red Hat: CVE-2025-21605: redis: Redis DoS Vulnerability due to unlimited growth of output buffers abused by unauthenticated client (Multiple Advisories)

A flaw was found in the Redis server. This flaw allows an unauthenticated client to cause an unlimited growth of output buffers until the server runs out of memory or is killed. By default, the Redis configuration does not limit the output buffer of normal clients (see client-output-buffer-limit). Therefore, the output buffer can grow unlimitedly over time. As a result, the service is exhausted, and the memory is unavailable.

When password authentication is enabled on the Redis server but no password is provided, the client can still cause the output buffer to grow from "NOAUTH" responses until the system runs out of memory.