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DeepSeek Harness Flaw Let AI Agents Disable Their Own File Sandbox Without Approval

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security

Source: The Hacker NewsSeptember 9, 2026

Summary

DeepSeek Harness, an open-source tool for running AI coding agents in a sandbox (an isolated environment where programs can only access certain files), had a critical flaw that let an agent disable its own sandbox protections with a single command. An attacker could trick the agent into calling the tool's web interface to switch to a 'danger-full-access' mode, allowing the agent to write files outside its workspace without approval, though the fix was deployed on August 27.

Solution / Mitigation

Install version 0.1.2-alpha.2 or later from npm. The CVE record names 0.1.2-alpha.1 as fixed (released August 27), but the first fixed release published to npm is 0.1.2-alpha.2 (August 30). The current npm release, 0.1.2-rc.1 (September 3), also carries the fix. If you cannot upgrade, stop the web interface when not in use and remove any tunnel, proxy, or port forward that reaches it.