GHSA-532v-xpq5-8h95 Electron: Use-after-free in offscreen child window paint callback

• npm electron: < 39.8.1 → fixed in 39.8.1 • npm electron: >= 40.0.0-alpha.1, < 40.7.0 → fixed in 40.7.0 • npm electron: >= 41.0.0-alpha.1, < 41.0.0 → fixed in 41.0.0

Impact Apps that use offscreen rendering and allow child windows via `window.open()` may be vulnerable to a use-after-free. If the parent offscreen `WebContents` is destroyed while a child window remains open, subsequent paint frames on the child dereference freed memory, which may lead to a crash or memory corruption. Apps are only affected if they use offscreen rendering (`webPreferences.offscreen: true`) and their `setWindowOpenHandler` permits child windows. Apps that do not use offscreen rendering, or that deny child windows, are not affected. Workarounds Deny child window creation from offscreen renderers in your `setWindowOpenHandler`, or ensure child windows are closed before the parent is destroyed. Fixed Versions • `41.0.0` • `40.7.0` • `39.8.1` For more information If there are any questions or comments about this advisory, please email [email protected]