Electron: Out-of-bounds read in second-instance IPC on macOS and Linux

### Impact On macOS and Linux, apps that call `app.requestSingleInstanceLock()` were vulnerable to an out-of-bounds heap read when parsing a crafted second-instance message. Leaked memory could be delivered to the app's `second-instance` event handler. This issue is limited to processes running as the same user as the Electron app. Apps that do not call `app.requestSingleInstanceLock()` are not affected. Windows is not affected by this issue. ### Workarounds There are no app side workarounds, developers must update to a patched version of Electron. ### Fixed Versions * `41.0.0` * `40.8.1` * `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)