Electron: contextBridge object copy honors prototype setters

### Impact 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. Apps that only accept primitive arguments, or that validate object arguments, are not affected. ### Workarounds Validate objects received from untrusted content with own-property checks (`Object.hasOwn`), or copy them onto a null-prototype object before use. ### Fixed Versions * `42.0.0-beta.4` * `41.2.2` * `40.9.2` * `39.8.9` ### For more information If you have any questions or comments about this advisory, email Electron at [[email protected]](mailto:[email protected])

Source published

5 Aug 2026 17:41:20 UTC

Source modified

5 Aug 2026 17:56:07 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

Publisher rating · MODERATE