CVE-2026-70610: 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 security@electronjs.org
Other sources
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.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/electronto a version that resolves this vulnerability.Fixed in 42.0.0-beta.4 - Upgrade
Upgrade
npm/electronto a version that resolves this vulnerability.Fixed in 41.2.2 - Upgrade
Upgrade
npm/electronto a version that resolves this vulnerability.Fixed in 40.9.2 - Upgrade
Upgrade
npm/electronto a version that resolves this vulnerability.Fixed in 39.8.9 - Upgrade
Upgrade
Electronto a version that resolves this vulnerability.Fixed in 39.8.9 - Upgrade
Upgrade
Electronto a version that resolves this vulnerability.Fixed in 40.9.2 - Upgrade
Upgrade
Electronto a version that resolves this vulnerability.Fixed in 41.2.2 - Upgrade
Upgrade
Electronto a version that resolves this vulnerability.Fixed in 42.0.0-beta.4 - Configuration
Validate objects received from untrusted content with own-property checks using Object.hasOwn, or copy them onto a null-prototype object before use.
Electron preload code own-property validation for objects received from untrusted content = Use Object.hasOwn or copy objects onto a null-prototype object
Event History
Frequently Asked Questions
What is the severity of CVE-2026-70610?
CVE-2026-70610 has a medium severity score of 5.4.
How does CVE-2026-70610 impact applications using Electron?
CVE-2026-70610 allows attacker-influenced prototypes to potentially compromise preload code in Electron applications.
What are the conditions necessary for CVE-2026-70610 to exploit an application?
CVE-2026-70610 affects applications if their preload code accepts object arguments from untrusted content across the contextBridge.
How can developers mitigate the risks associated with CVE-2026-70610?
To mitigate CVE-2026-70610, developers should validate and sanitize any object arguments passed into preload code.
In which versions of Electron is CVE-2026-70610 present?
CVE-2026-70610 affects specific versions of Electron that allow unsafe behavior in contextBridge interactions.