The vulnerability is an unauthenticated SQL injection located in the login.jsp endpoint of Linknat VOS2009 and VOS3000. By manipulating the username field in a POST request, an attacker can inject arbitrary SQL statements and subsequently retrieve query results in a later session. The result is the extraction of plaintext credentials and other database contents with database administrator level privileges, demonstrating a significant threat to data confidentiality. This weakness is classified as CWE-89.

All installations of Kunshi Network Technology’s Linknat VOS2009 and Linknat VOS3000 running version 2.1.2.0 or earlier are affected. The flaw exists within the login form of both product lines and allows remote users to reach the web interface without any form of authentication.

The CVSS score of 9.3 indicates a critical severity, though the EPSS score of less than 1% suggests low current exploitation probability. The vulnerability is not yet listed in CISA KEV, but its remote, unauthenticated nature and potential to expose DBA‑level data make it a high‑risk asset. Attackers can exploit the flaw over the network by sending crafted POST requests to the login.jsp endpoint from any reachable host, bypassing any authentication controls.