CVE-2026-34765

Workarounds

Deny window.open() in renderers that load untrusted content by returning { action: 'deny' } from setWindowOpenHandler. Avoid granting child windows more permissive webPreferences than their opener.

Fixed Versions

• 42.0.0-alpha.5
• 41.1.0
• 40.8.5
• 39.8.5

For more information

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

When a renderer calls window.open() with a target name, Electron did not correctly scope the named-window lookup to the opener's browsing context group. A renderer could navigate an existing child window that was opened by a different, unrelated renderer if both used the same target name. If that existing child was created with more permissive webPreferences (via setWindowOpenHandler's overrideBrowserWindowOptions), content loaded by the second renderer inherits those permissions.

Apps are only affected if they open multiple top-level windows with differing trust levels and use setWindowOpenHandler to grant child windows elevated webPreferences such as a privileged preload script. Apps that do not elevate child window privileges, or that use a single top-level window, are not affected.

Apps that additionally grant nodeIntegration: true or sandbox: false to child windows (contrary to the security recommendations) may be exposed to arbitrary code execution.

CVE-2026-34765 has a CVSS score of 6.0 (Medium). The vector is network-reachable, low 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 (39.8.5, 40.8.5, 41.1.0, 42.0.0-alpha.5); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-34765? CVE-2026-34765 is a medium-severity security vulnerability in electron (npm), affecting versions < 39.8.5. It is fixed in 39.8.5, 40.8.5, 41.1.0, 42.0.0-alpha.5.
2. How severe is CVE-2026-34765? CVE-2026-34765 has a CVSS score of 6.0 (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-2026-34765? electron (npm) versions < 39.8.5 is affected.
4. Is there a fix for CVE-2026-34765? Yes. CVE-2026-34765 is fixed in 39.8.5, 40.8.5, 41.1.0, 42.0.0-alpha.5. Upgrade to this version or later.
5. Is CVE-2026-34765 exploitable, and should I be worried? Whether CVE-2026-34765 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-2026-34765 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-2026-34765?
   • Upgrade electron to 39.8.5 or later
   • Upgrade electron to 40.8.5 or later
   • Upgrade electron to 41.1.0 or later
   • Upgrade electron to 42.0.0-alpha.5 or later