CVE-2026-70608: Electron: Sandboxed iframe can bypass the allow-popups restriction via the OpenURL navigation path

Severity: high (CVSS 7.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% 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-693

Description

Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to 39.8.10, 41.10.3, and 42.0.1, a sandboxed iframe without the allow-popups keyword could still open a new window or trigger setWindowOpenHandler with no user interaction because new-window navigations taking the OpenURL path did not apply the iframe sandbox popup restriction. Apps that embed untrusted content in sandboxed iframes and rely on the absence of allow-popups to prevent window creation are affected, while apps that deny window creation in setWindowOpenHandler or do not embed untrusted content in sandboxed iframes are not affected. This issue is fixed in 39.8.10, 41.10.3, and 42.0.1.

Affected products

electron: before 39.8.8; from 40.0.0 before 41.10.3; from 42.0.0 before 42.0.1 — fixed in 39.8.8, 41.10.3, 42.0.1

How to fix

Upgrade to a fixed version: electron 39.8.8, 41.10.3, 42.0.1. Check the vendor advisory for mitigations.

References

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