CVE-2025-43960: 
PHP vulnerability analysis and mitigation

Adminer 4.8.1, when using Monolog for logging, allows a Denial of Service (memory consumption) vulnerability through PHP Object Injection. The vulnerability was discovered and disclosed on August 25, 2025, affecting Adminer installations that utilize Monolog for logging functionality. This security flaw enables remote, unauthenticated attackers to trigger excessive memory consumption by sending malicious serialized objects (NVD, GitHub POC).

The vulnerability stems from improper handling of serialized data in Monolog integration within Adminer 4.8.1. Attackers can exploit this by sending a crafted serialized payload (e.g., using s:1000000000) that forces excessive memory usage. The vulnerability has received a CVSS v3.1 Base Score of 8.6 (HIGH) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L. The issue is classified under CWE-502 (Deserialization of Untrusted Data) (NVD, GitHub POC).

When successfully exploited, the vulnerability renders Adminer's interface unresponsive and causes a server-level Denial of Service. While the server may recover after several minutes of a single attack, multiple simultaneous requests can cause a complete crash requiring manual intervention. In shared environments where Adminer crashes can affect other services, the impact severity increases (GitHub POC).

Several mitigation measures are recommended: 1) Avoid using unserialize() on untrusted data within Adminer and Monolog, 2) Enforce memory limits (memorylimit) in PHP to prevent excessive resource consumption, 3) Use allowedclasses in unserialize() to restrict deserialization of unauthorized classes. Organizations should also consider updating to a patched version when available (GitHub POC).