DescriptionAdminer 4.16.0 through 6.0.1 contain a pre-authentication Server-Side Request Forgery (SSRF) vulnerability in the optional Elasticsearch driver (plugins/drivers/elastic.php), fixed in 6.0.2. Because adminer/include/auth.inc.php invokes Driver::connect() before the login result is validated, an unauthenticated attacker who submits crafted auth[server], auth[username], and auth[password] parameters can cause the Adminer server to issue an HTTP GET request (via get_url()/file_get_contents()) to an arbitrary reachable host and port. The driver validates only general server syntax and does not block loopback, private, link-local, or other reserved addresses; if no port is given it appends the default 9200, and Adminer's generic port check rejects ports below 1024. Selected JSON error fields from non-2xx Elasticsearch-style responses, as well as connection failures, are rendered on the login page, providing a port-scanning oracle and enabling internal network reconnaissance and service fingerprinting. Exploitation requires that the optional Elasticsearch driver be explicitly deployed (e.g., via the adminer/elastic.php template or an adminer_object() configuration; it is not loaded in a default build) and that PHP allow_url_fopen be enabled.