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 [[email protected]](mailto:[email protected])

Source published

5 Aug 2026 17:27:18 UTC

Source modified

20 Aug 2026 05:15:07 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Publisher rating · HIGH