CVE-2026-70610: Electron: contextBridge object copy honors prototype setters

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-05 · updated 2026-10-08
Weakness: CWE-1321

Description

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.

Affected products

electron: before 39.8.9; from 40.0.0 before 40.9.2; from 41.0.0 before 41.2.2; 42.0.0-alpha1, 42.0.0-alpha2, 42.0.0-alpha3, 42.0.0-alpha4, 42.0.0-alpha5, 42.0.0-alpha6 (+3) — fixed in 39.8.9, 40.9.2, 41.2.2

How to fix

Upgrade to a fixed version: electron 39.8.9, 40.9.2, 41.2.2. Check the vendor advisory for mitigations.

References

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