CVE-2026-70612

Electron: Sandboxed iframes can launch external protocol handlers

Workarounds

Install a setPermissionRequestHandler that denies the openExternal permission for untrusted content.

Fixed Versions

• 42.0.0-beta.3
• 41.2.1
• 40.9.0
• 39.8.8

For more information

If you have any questions or comments about this advisory, email Electron at [email protected]

Requests to open external protocol URLs from web content did not take iframe sandbox restrictions into account, so a sandboxed iframe could cause an OS-registered external application to be launched. The frame's sandbox state was also not made available to the app's permission handlers.

Apps are only affected if they render untrusted content in sandboxed iframes and grant the openExternal permission (granted by default when no setPermissionRequestHandler is installed). Apps whose permission handler denies openExternal for untrusted content are not affected.

CVE-2026-70612 has a CVSS score of 5.4 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (39.8.8, 40.9.0, 41.2.1, 42.0.0-beta.3); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

1. What is CVE-2026-70612? CVE-2026-70612 is a medium-severity security vulnerability in electron (npm), affecting versions < 39.8.8. It is fixed in 39.8.8, 40.9.0, 41.2.1, 42.0.0-beta.3.
2. How severe is CVE-2026-70612? CVE-2026-70612 has a CVSS score of 5.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of electron are affected by CVE-2026-70612? electron (npm) versions < 39.8.8 is affected.
4. Is there a fix for CVE-2026-70612? Yes. CVE-2026-70612 is fixed in 39.8.8, 40.9.0, 41.2.1, 42.0.0-beta.3. Upgrade to this version or later.
5. Is CVE-2026-70612 exploitable, and should I be worried? Whether CVE-2026-70612 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-70612 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-70612?
   • Upgrade electron to 39.8.8 or later
   • Upgrade electron to 40.9.0 or later
   • Upgrade electron to 41.2.1 or later
   • Upgrade electron to 42.0.0-beta.3 or later

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