[waleedlatif1]

Summary

• The pool brokers sandbox fetch() on the app side. When it gave up on an execution (host timeout, caller abort, worker loss), the outbound request kept running. The only limit was the script-settable idle timeout, which a slow-drip server keeps resetting. The owner's execution slot was already free, so per-owner limits didn't cover these requests
• Replace the cancelled flag on each pending execution with an abort controller that fires on every give-up path. Pass it into secureFetchWithValidation, which already honors signal through DNS validation and the pinned request
• Cap each fetch at the execution's own host time budget (timeoutMs + 1s grace), via AbortSignal.any([abort, AbortSignal.timeout(...)]). The pool gives up on the execution no later than that, so the cap never fires while the execution is alive. It only bounds a fetch the script left running after returning, whose response nothing can read
• Deliberately not aborted on a normal result: a fire-and-forget request (e.g. a webhook POST) is still sent. Only the wait for its unread response is bounded
• A per-fetch composite signal keeps abort listeners off the shared per-execution signal, so fan-out (Promise.all of many fetches) can't trip MaxListenersExceededWarning or pile up stale redirect-hop listeners on it

Type of Change

• Bug fix (security / resource)

Testing

• test-isolated-vm-remote-e2e.ts: 4 new checks against a server that never answers:
  • timed-out execution: the fetch, started late in the run, is dropped within 400ms of the timeout
  • cancelled execution
  • worker killed mid-fetch
  • script returns with a POST still in flight: the request reaches the server and is dropped after the time budget
• 25/25 pass. Removing each guard on its own turns exactly its own check red: timeout abort, cancel abort, worker-loss abort, time cap. All four new checks fail on staging
• AbortSignal.any + AbortSignal.timeout behave identically under Node 22 and Bun
• isolated-vm.test.ts + isolated-vm-worker-hardening.test.ts 28/28; biome, check:test-patterns, check:comment-hygiene, check:utils, check:boundaries, check:source-conventions; full gate left to CI

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing (new tests pass the test-audit authoring gate)
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

🤖 Generated with Claude Code

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1 Skipped Deployment

Project	Deployment	Actions	Updated
docs	Skipped		Nov 7, 2026 10:29pm UTC

[greptile-apps]

Confidence Score: 5/5

[Medium impact] The PR appears safe to merge; no blocking issues were found.

Summary

Bounds sandbox fetches when an execution times out, is cancelled, or loses its worker. Requests left running after a normal return get a time limit instead of being stopped immediately.

• Sandbox fetches stop when their execution ends or their time budget runs out.

_{Reviews (4) · Last reviewed commit: "test(sandbox): pin that a fire-and-forge..." · Reviewed by Greptile}

[cubic-dev-ai]

All reported issues were addressed across 2 files

<sub>Reply with feedback, questions, or to request a fix.

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[waleedlatif1]

@greptile

[waleedlatif1]

@cubic-dev-ai review this PR

[cubic-dev-ai]

@cubic-dev-ai review this PR

@waleedlatif1 I have started the AI code review. It will take a few minutes to complete.

[cubic-dev-ai]

All reported issues were addressed across 2 files

<sub>Reply with feedback, questions, or to request a fix.

Turn on auto-fix | Re-trigger cubic</sub>

[waleedlatif1]

@greptile

[waleedlatif1]

@cubic-dev-ai review this PR

[cubic-dev-ai]

@cubic-dev-ai review this PR

@waleedlatif1 I have started the AI code review. It will take a few minutes to complete.

[cubic-dev-ai]

No issues found across 2 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

_{Turn on auto-fix | Re-trigger cubic}