GHSA-9f4c-93c8-jc8g CVE-2026-70608

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

High npm

Severity: 7.2 / 10; High · CVSS 3.1
Exploit chance (EPSS): 0.43%; Chance of exploitation in the next 30 days. Higher than 37.31% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-1021 Improper Restriction of Rendered UI Layers or Frames; CWE-693 Protection Mechanism Failure
Fix: 42.0.1; Upgrade electron to this version or later

Description

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

Affected versions

npm

Package	Vulnerable	Fixed in
electron	`>= 42.0.0-alpha.1, < 42.0.1`	`42.0.1`
electron	`>= 40.0.0-alpha.1, < 41.10.3`	`41.10.3`
electron	`< 39.8.10`	`39.8.10`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

electron npm → `42.0.1`

npm

npm install electron@42.0.1

yarn

yarn add electron@42.0.1

pnpm

pnpm add electron@42.0.1

Severity breakdown

CVSS 3.1 7.2

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Changed
Confidentiality: Low
Integrity: Low
Availability: None

Weakness

CWE-1021: Improper Restriction of Rendered UI Layers or Frames

The web application does not restrict or incorrectly restricts frame objects or UI layers that belong to another application or domain.

How to prevent it

Implementation: The use of X-Frame-Options allows developers of web content to restrict the usage of their application within the form of overlays, frames, or iFrames. The developer can indicate from which domains can frame the content. The concept of X-Frame-Options is well documented, but implementation of this protection mechanism is in development to cover gaps. There is a need for allowing frames from multiple domains.
Implementation: A developer can use a "frame-breaker" script in each page that should not be framed. This is very helpful for legacy browsers that do not support X-Frame-Options security feature previously mentioned. It is also important to note that this tactic has been circumvented or bypassed. Improper usage of frames can persist in the web application through nested frames. The "frame-breaking" script does not intuitively account for multiple nested frames that can be presented to the user.
Implementation: This defense-in-depth technique can be used to prevent the improper usage of frames in web applications. It prioritizes the valid sources of data to be loaded into the application through the usage of declarative policies. Based on which implementation of Content Security Policy is in use, the developer should use the "frame-ancestors" directive or the "frame-src" directive to mitigate this weakness. Both directives allow for the placement of restrictions when it comes to allowing embedded content.
Implementation: In addition to frames or iframes as previously mentioned, the web application is expected to place restrictions on whether it is allowed to be rendered within objects, embed, or applet elements.

CWE-693: Protection Mechanism Failure

The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.

References

Packages

github.com/electron/electron

Timeline

Aug 5, 2026 Published
Oct 8, 2026 Last updated by the source
Oct 31, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-qqvq-6xgj-jw8g Electron affected by libvpx's heap buffer overflow in vp8 encoding	High Known exploited	Also affects electron
GHSA-j7hp-h8jx-5ppr libwebp: OOB write in BuildHuffmanTable	High Known exploited	Also affects electron
GHSA-995f-9x5r-2rcj Heap buffer overflow in GPU	Critical Known exploited	Also affects electron
GHSA-jr5w-w6x2-84p9 Electron: Mitigation for compromised eMudhra intermediate certificates	High	Also affects electron
GHSA-h3v5-h239-pg29 Electron: Off-screen rendering on macOS trusts GPU-supplied frame geometry	Low	Also affects electron
GHSA-3qxv-5xgr-q7w9 Electron: Frame subscription trusts GPU-supplied frame geometry	Low	Also affects electron
GHSA-997q-gvvc-jwmx Electron: openExternal permission requests can be attributed to the wrong origin	Medium	Also affects electron
GHSA-fw47-9c62-h3vw Electron: HID and USB permission checks can be attributed to the wrong origin	Medium	Also affects electron

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