CVE-2026-90919 describes a remote code execution vulnerability in ModelTC's LightLLM product through version 1.2.0. The vulnerability exists in the Config Server component, specifically in the unauthenticated /visual_register WebSocket endpoint. This endpoint passes the first client frame directly to Python's pickle.loads() function without validation, enabling attackers to craft malicious serialized payloads containing a __reduce__ method. When deserialized, these payloads execute arbitrary code with the privileges of the Config Server process. The CVSS 4.0 base score is 9.3, indicating critical severity with network attack vector, no required privileges or user interaction, and high impact on confidentiality, integrity, and availability.

Successful exploitation allows remote attackers to execute arbitrary code on the Config Server with its process privileges, potentially leading to full system compromise or unauthorized control over the affected service. The vulnerability is exploitable without authentication and requires only network access to the Config Server port.

No patch or official fix information is provided in the available data. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict network access to the Config Server port to trusted sources only to prevent unauthorized exploitation.