René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"V8 Maglev JIT causes STATUS_STACK_BUFFER_OVERRUN (0xC0000409) on Windows 11 Insider build 26200","articleBody":"## What happened?\n\nNode.js processes crash with exit code `-1073740791` (`0xC0000409` / `STATUS_STACK_BUFFER_OVERRUN`) within 20-70 seconds of startup when running a non-trivial application (WebSocket server with HTTP, Telegram bot polling, and plugin system) on Windows 11 Insider (Canary channel).\n\nThe crash is caused by V8's **Maglev** JIT compiler tier. Workaround: `--no-maglev` flag eliminates the crash entirely.\n\n## Reproduction\n\n**Environment:**\n- Node.js: v25.8.0\n- V8: 14.1.146.11-node.20\n- OS: Windows 11 Pro for Workstations, Insider Canary build **10.0.26200.0**\n- Arch: x64\n\n**Steps:**\n1. Run a long-lived Node.js application that uses `fetch()`, WebSocket, and timers on Windows 11 Insider build 26200\n2. Process crashes with exit code `-1073740791` (0xC0000409) within 20-70 seconds\n3. No JavaScript stack trace — the crash is in native JIT-compiled code via `__fastfail`\n\n**Flags tested:**\n\n| Flag | Crash? | `fetch()` works? |\n|------|--------|------------------|\n| (none) | **Yes** — crashes in 20-70s | Yes |\n| `--jitless` | No | **No** — undici fetch broken |\n| **`--no-maglev`** | **No** | **Yes** |\n| `--no-turbofan` | No | Yes |\n\n`--no-maglev` is the minimal workaround — disabling only the Maglev tier prevents the crash while keeping TurboFan and fetch() functional.\n\n**Additional context:**\n- A bare Node.js HTTP server (`http.createServer`) does NOT crash — the issue requires enough code to trigger Maglev optimization\n- Crash bypasses Windows Error Reporting (`__fastfail` / SEH)\n- Windows Event Viewer shows the Insider build has kernel-level instability (BlueScreen events, VIDEO_ENGINE_TIMEOUT_DETECTED), suggesting stricter CFG enforcement\n- The same application runs without issues on Windows Server 2019 and stable Windows builds\n\n## Expected behavior\n\nNode.js should not crash with STATUS_STACK_BUFFER_OVERRUN. Maglev-compiled code should respect Windows CFG/CET enforcement on Insider builds.\n\n## Workaround\n\nPass `--no-maglev` as a command-line flag (cannot be set via `NODE_OPTIONS`):\n\n```\nnode --no-maglev app.js\n```","author":{"url":"https://github.com/vicjayjay","@type":"Person","name":"vicjayjay"},"datePublished":"2026-03-15T09:51:36Z","url":"https://github.com/nodejs/node/issues/62260"}