GHSA-fm4g-76c9-7w69

The `DigestAuth` server middleware's stale-nonce cleanup uses an inverted comparison: it removes *fresh* nonces and stops at the first *stale* one. Because a new nonce is created for every unauthenticated challenge, an attacker can drive the nonce map to grow without bound until the JVM runs out of heap.

## Impact

Unauthenticated remote denial of service (gradual heap exhaustion / OOM) against any service using DigestAuth. The leak is persistent.

## Preconditions

- Application uses `DigestAuth` on at least one route.

## Workarounds

- Front the DigestAuth protected routes with a rate limiter to slow the leak. - Restart periodically.

## Fixes

- The eviction logic is corrected. - A max cache size of 1000000 is imposed to protected against a burst between evictions. This limit is not yet configurable.