CVE-2026-82533: Authentication Bypass in @deepseek-ai/dsh-client-connection Allows Full Agent Control
Summary
CVE-2026-82533: DeepSeek Harness contains an authentication bypass vulnerability in local HTTP control-plane API. Affects @deepseek-ai/dsh-client-connection versions < 0.1.2-alpha.1. Fixed in 0.1.2-alpha.1. How to fix ↓
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Background
The @deepseek-ai/dsh-client-connection package is part of the DeepSeek Harness, which provides a control-plane API for managing agents in a local environment. This package is designed to facilitate communication and command execution between users and agents. However, it has been found to have a critical vulnerability that compromises its security, allowing unauthorized access to sensitive functionalities.
Vulnerability Detail
DeepSeek Harness before version 0.1.2-alpha.1 contains an authentication bypass vulnerability in its local HTTP control-plane API. This flaw arises because the server validates only the client-supplied Host header value instead of the actual TCP connection origin. Attackers can exploit this vulnerability by supplying a spoofed Host header, which grants them full control over the agent. This includes the ability to execute privileged commands, escalate session approval policies, and retrieve stored conversations without needing any credentials or API keys. The CVSS score for this vulnerability is 9.6, indicating a critical severity level.
How To Fix
Minimum fixed version
0.1.2-alpha.1
This is the first release that contains the fix.
npm install @deepseek-ai/dsh-client-connection@0.1.2-alpha.1Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, you can restrict access to the local HTTP control-plane API by implementing network-level controls, such as firewall rules, to limit incoming connections to trusted sources only. However, this is not a permanent solution and updating the package is recommended.
Conclusion
The authentication bypass vulnerability in the @deepseek-ai/dsh-client-connection package poses a significant risk to users of DeepSeek Harness. It is crucial to update to the patched version to mitigate this risk and ensure the security of your application.
See every vulnerability recorded for @deepseek-ai/dsh-client-connection →
FAQ
The vulnerability is an authentication bypass that allows attackers to gain unauthorized access to the control-plane API of DeepSeek Harness.
You can check if your application is affected by using the Vulert playground at Vulert Scanner, which analyzes your package-lock.json for vulnerabilities.
If exploited, attackers can execute privileged commands, escalate session approval policies, and access sensitive data without authentication.
Yes, the vulnerability has been patched in version 0.1.2-alpha.1 of the @deepseek-ai/dsh-client-connection package.
If immediate updates are not possible, implement network-level controls to restrict access to the API as a temporary workaround.
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