Electron: Use-after-free in PowerMonitor on Windows and macOS

### Impact Apps that use the `powerMonitor` module may be vulnerable to a use-after-free. After the native `PowerMonitor` object is garbage-collected, the associated OS-level resources (a message window on Windows, a shutdown handler on macOS) retain dangling references. A subsequent session-change event (Windows) or system shutdown (macOS) dereferences freed memory, which may lead to a crash or memory corruption. All apps that access `powerMonitor` events (`suspend`, `resume`, `lock-screen`, etc.) are potentially affected. The issue is not directly renderer-controllable. ### Workarounds There are no app side workarounds, you must update to a patched version of Electron. ### Fixed Versions * `41.0.0-beta.8` * `40.8.0` * `39.8.1` * `38.8.6` ### For more information If there are any questions or comments about this advisory, please email [security@electronjs.org](mailto:security@electronjs.org)