Critical

DeepSeek Harness contains an authentication bypass vulnerability in local HTTP control-plane API

  • Disclosed: 08.09.2026
  • Updated: 11.10.2026 10:22

DeepSeek Harness before 0.1.2-alpha.1 contains an authentication bypass vulnerability in its local HTTP control-plane API that allows attackers to gain full agent control by supplying a spoofed Host header, as the server validates only the client-supplied Host header value rather than the actual TCP connection origin. Attackers can exploit this flaw to invoke privileged commands such as commands/execute with danger-full-access permissions, escalate session approval policies to unconfined execution, and retrieve all stored conversations without any credential or API key.

Affected software

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PlatformPackageVulnerable versionsFixed in
npm package @deepseek-ai/dsh-client-connection < 0.1.2-alpha.1 0.1.2-alpha.1

References

CVSS score 9.6/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Weakness (CWE)
CWE-807
Platform
npm
Package
@deepseek-ai/dsh-client-connection
Disclosed
08.09.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-8m2g-8cgm-3vcp - CC BY 4.0

Vulnerability history: @deepseek-ai/dsh-client-connection

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

This is the only known vulnerability of this package.

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