DeepSeek Harness critical vulnerability QVD-2026-57410 disclosed with CVSS 9.8
QiAnXin disclosed on Aug 24 a critical unauthenticated RCE in DeepSeek Harness v0.1.1-rc.2 with CVSS 9.8; POC is public.
On August 24, the QiAnXin Threat Intelligence Center disclosed an unauthenticated remote code execution vulnerability in DeepSeek Harness (DSH). The vulnerability is numbered QVD-2026-57410, rated critical, with a CVSS 3.0 score of 9.8. The POC is public.
The root cause is a flaw in the platform's validation of HTTP Host request headers. Attackers can forge Host headers to bypass the /api trust fence, call internal restricted RPC methods, register fake large model providers, and drive Agent tools to execute arbitrary system commands.
The attack chain does not require a valid API Key. After successful exploitation, attackers can execute commands on the target server with dsh service process privileges, steal sensitive data, plant backdoors, and move laterally. Exploitation requires the DeepSeek Harness management API to be exposed to the public network without strict Host header validation. No in-the-wild exploitation has been observed as of disclosure.
The affected version is DeepSeek Harness 0.1.1-rc.2. Security agencies recommend isolating the management API port from the public network and configuring strict Host header validation rules at the reverse proxy layer.