Electron: contextBridge object copy honors prototype setters

Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to 39.8.9, 40.9.2, 41.2.2, and 42.0.0-beta.4, objects copied across the contextBridge boundary from untrusted content could carry an attacker-influenced prototype, enabling prototype-pollution-style attacks against preload code despite context isolation being enabled. Apps are only affected if their preload code accepts object arguments from untrusted content and reads properties from them without own-property checks, while apps that only accept primitive arguments or validate object arguments are not affected. This issue is fixed in 39.8.9, 40.9.2, 41.2.2, and 42.0.0-beta.4.

Source published

5 Aug 2026 17:41:03 UTC

Source modified

6 Aug 2026 14:31:10 UTC

Observed here

23 Oct 2026 15:48:27 UTC

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CVSS 3.1 · 5.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N