CVE-2025-43960

Vulnerability

Overview

CVE-2025-43960 is a PHP Object Injection vulnerability in Adminer version 4.8.1, specifically impacting instances that employ the Monolog logging library. The root cause is the insecure deserialization of untrusted user input without proper validation. An attacker can craft a malicious serialized payload, such as one containing an 's:1000000000' string, which when deserialized by Adminer forces the PHP interpreter to allocate an enormous memory block. This leads to rapid and severe memory exhaustion on the server [1][2].

Attack

Vector

The vulnerability is exploitable remotely by an unauthenticated attacker with no user interaction required. The attack vector does not require prior authentication or any specific privileges, making it easily accessible over the network. The crafted serialized object is sent to the Adminer interface, and due to the lack of validation in the deserialization process, the Monolog logging mechanism will process the malicious input, triggering excessive memory allocation. This can be achieved with a single request, but multiple concurrent requests exacerbate the impact [1][2].

Impact

Successful exploitation results in a Denial of Service (DoS) condition. The Adminer web interface becomes unresponsive, and the server itself may suffer from heavy memory consumption, potentially affecting other services running on the same system. While the server might recover after several minutes once the memory is reclaimed, multiple simultaneous attacks can cause a complete crash, requiring manual administrator intervention to restore service. The official CVSS v3.1 base score is 7.5 (High), with a possibility of 8.6 (High) in shared environments where the DoS affects other tenants [1][2].

Mitigation

As of August 2025, users are advised to upgrade Adminer to a version beyond 4.8.1, as the vulnerability has been addressed in subsequent releases. Mitigation recommendations include avoiding the use of unserialize() on untrusted data, enforcing strict PHP memory limits (memory_limit), and restricting deserialization to authorized classes by using the allowed_classes parameter in unserialize() to prevent arbitrary object injection [2]. The official Adminer repository is available for reference and updates [3].