Cursor Desktop sandbox escape via agent-controlled working directory

Summary

Cursor runs agent terminal commands in a sandbox by default, and the sandbox grants write access to the command's working directory. A flaw was identified in how the agent could modify the working_directory parameter, which could cause the sandbox to include writable paths outside the intended workspace.

Impact

A malicious agent could set working_directory to a sensitive location and write arbitrary files outside the workspace under the user's privileges. This enables non-sandboxed Remote Code Execution — for example by overwriting the cursorsandbox helper so later commands run unsandboxed — with no user interaction beyond a benign prompt.

Remediation

Update Cursor to version 3.0. The sandbox no longer grants write access based on an agent-controlled working directory.

Credit

Cato AI Labs