CVE-2026-70610 in Electron
Summary
by MITRE • 08/05/2026
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.
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Analysis
by VulDB Data Team • 08/05/2026
The vulnerability described represents a critical prototype pollution weakness in the Electron framework that undermines the security model designed to isolate untrusted content from trusted preload code. This issue specifically affects versions prior to 39.8.9, 40.9.2, 41.2.2, and 42.0.0-beta.4 where the contextBridge mechanism fails to properly sanitize objects passed across security boundaries. The flaw occurs when untrusted content attempts to manipulate object prototypes during cross-context communication, creating opportunities for attackers to inject malicious properties into the prototype chain that can then be exploited by preload scripts.
The technical execution of this vulnerability relies on the improper handling of object copying through Electron's contextBridge API which is designed to facilitate secure communication between the main process and renderer processes. When objects are transferred from untrusted renderer contexts to trusted preload code, the framework fails to perform adequate prototype validation, allowing attackers to inject properties that can be accessed by subsequent operations in the preload context. This bypasses the intended security isolation that should prevent untrusted code from influencing the behavior of trusted code execution environments.
The operational impact of this vulnerability is significant as it enables attackers to perform prototype pollution attacks that can lead to various malicious outcomes including privilege escalation, information disclosure, and arbitrary code execution within the application's security boundaries. The vulnerability specifically targets applications that accept object arguments from untrusted sources in their preload scripts without implementing proper own-property checks, making these applications susceptible to exploitation even when context isolation is properly configured. This represents a fundamental breakdown in Electron's security model where the framework's attempt to provide secure cross-context communication becomes a vector for attacks.
The fix implemented in versions 39.8.9, 40.9.2, 41.2.2, and 42.0.0-beta.4 addresses this issue by strengthening the validation mechanisms within the contextBridge implementation to prevent prototype pollution during object transfer operations. Organizations should immediately upgrade to these patched versions to mitigate the risk, while also reviewing their preload code implementations to ensure that proper input validation is in place for any objects received from untrusted sources. This vulnerability aligns with CWE-471 which addresses the weakness of using an incorrect function or method parameter, and maps to ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation' through improper input handling.
Applications that properly validate object arguments or only accept primitive data types are not vulnerable to this specific attack vector, highlighting the importance of defensive programming practices in security-sensitive contexts. The remediation approach emphasizes the need for robust input sanitization and proper prototype validation when implementing cross-context communication mechanisms in frameworks like Electron where security boundaries must be strictly enforced.