CVE-2026-70608: Electron: Sandboxed iframe can bypass the allow-popups restriction via the OpenURL navigation path
Impact 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. Apps that deny window creation in setWindowOpenHandler, or that do not embed untrusted content in sandboxed iframes, are not affected.
Workarounds Return { action: 'deny' } from setWindowOpenHandler for any content you do not trust, rather than relying on the iframe sandbox alone.
Fixed Versions 42.0.1 41.10.3 39.8.10
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 39.8.10, 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.
— 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 39.8.10 - Upgrade
Upgrade
npm/electronto a version that resolves this vulnerability.Fixed in 41.10.3 - Upgrade
Upgrade
npm/electronto a version that resolves this vulnerability.Fixed in 42.0.1 - Upgrade
Upgrade
Electronto a version that resolves this vulnerability.Fixed in 39.8.10 - Upgrade
Upgrade
Electronto a version that resolves this vulnerability.Fixed in 41.10.3 - Upgrade
Upgrade
Electronto a version that resolves this vulnerability.Fixed in 42.0.1 - Configuration
Return { action: 'deny' } from setWindowOpenHandler for any content you do not trust, rather than relying on the iframe sandbox alone.
Electron setWindowOpenHandler = { action: 'deny' }
Event History
Frequently Asked Questions
What is the severity of CVE-2026-70608?
The severity of CVE-2026-70608 is high, with a score of 7.2.
How do I fix CVE-2026-70608?
To fix CVE-2026-70608, ensure that the `allow-popups` keyword is included in your iframe sandbox attributes.
What are the potential impacts of CVE-2026-70608?
CVE-2026-70608 could allow a sandboxed iframe to open new windows without user interaction, bypassing intended restrictions.
Which software is affected by CVE-2026-70608?
CVE-2026-70608 affects the Electron framework used for building cross-platform desktop applications.
Is user interaction required to exploit CVE-2026-70608?
No, exploitation of CVE-2026-70608 does not require user interaction.