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Data breach Data exfiltration verified

Google Jules asynchronous coding agent vulnerable to multiple data exfiltration issues

Google (Jules) · Aug 13, 2025 · Coding agent

What happened

Johann Rehberger disclosed that Google Jules, Google's asynchronous coding agent, was vulnerable to multiple data exfiltration issues. Jules operates as a main agent that proposes a plan and then hands subtasks off to worker agents carrying different tools, and its system prompt and tooling could be steered via prompt injection to pull data off the developer's machine — an instance of the 'lethal trifecta' of agent risks. Findings were shared with Google before publication.

Loss / impact
Aug 13
2025
Data
Failure mode
Coding
Agent type

Causal vector

Multi-agent planner/worker design expands the injection surface; worker tools could be steered to exfiltrate local data

Source

Reported by Embrace The Red (Johann Rehberger). Verified against the primary report.

Read the original report ↗

How a spend firewall would have helped

Jules's planner-and-workers design expands the attack surface. Per-agent velocity limits on file and network reads, plus an egress allowlist on outbound calls, contain the exfiltration at the worker level — where the model has no authority to override policy.

The six rule types that contain this class of failure

Per-transaction cap

Any single spend above your ceiling is BLOCKED before it moves.

Daily total

Cumulative spend across all agent calls, bounded per day.

Velocity limit

Stops runaway retry loops — the #1 cause of overnight losses.

Merchant allowlist

Only approved destinations can ever receive funds.

Category rules

Flag high-risk classes (crypto, infra, refunds) for review.

Approval threshold

Above a value, the action waits for a human.

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