Adminer 4.8.1, when using Monolog for logging, allows a Denial of Service (memory consumption) via a crafted serialized payload (e.g., using s:1000000000), leading to a PHP Object Injection issue. Remote, unauthenticated attackers can trigger this by sending a malicious serialized object, which forces excessive memory usage, rendering Adminer’s interface unresponsive and causing a server-level DoS. While the server may recover after several minutes, multiple simultaneous requests can cause a complete crash requiring manual intervention.