Electron: SameSite cookie restrictions are not applied to windows opened from links

Impact

Pages opened into a new window from a link were loaded as if the app itself had navigated there rather than the page that contained the link, so the request was treated as same-site: SameSite=Strict cookies were sent and Sec-Fetch-Site did not identify the initiating page. Content shown in the app could use this to make a credentialed top-level request to another site that relies on SameSite cookies as a CSRF defence.

Apps are only affected if they load untrusted content and allow it to open new windows. Apps that deny new windows from untrusted content with setWindowOpenHandler are not affected.

Workarounds

Return { action: 'deny' } from setWindowOpenHandler for windows opened by untrusted content.

Fixed Versions

• 45.0.0-alpha.6
• 44.3.0
• 43.7.0
• 42.11.3

For more information

If you have any questions or comments about this advisory, email us at security@electronjs.org