CVE-2026-34774

Workarounds

Deny child window creation from offscreen renderers in your setWindowOpenHandler, or ensure child windows are closed before the parent is destroyed.

Fixed Versions

• 41.0.0
• 40.7.0
• 39.8.1

For more information

If there are any questions or comments about this advisory, please email [email protected]

Apps that use offscreen rendering and allow child windows via window.open() may be vulnerable to a use-after-free. If the parent offscreen WebContents is destroyed while a child window remains open, subsequent paint frames on the child dereference freed memory, which may lead to a crash or memory corruption.

Apps are only affected if they use offscreen rendering (webPreferences.offscreen: true) and their setWindowOpenHandler permits child windows. Apps that do not use offscreen rendering, or that deny child windows, are not affected.

Memory is accessed after it has been freed, leading to undefined behavior in native code. Typical impact: memory corruption, crash, or potential code execution.

CVE-2026-34774 has a CVSS score of 8.1 (High). 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 (39.8.1, 40.7.0, 41.0.0); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-34774? CVE-2026-34774 is a high-severity use after free vulnerability in electron (npm), affecting versions < 39.8.1. It is fixed in 39.8.1, 40.7.0, 41.0.0. Memory is accessed after it has been freed, leading to undefined behavior in native code.
2. How severe is CVE-2026-34774? CVE-2026-34774 has a CVSS score of 8.1 (High). 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-2026-34774? electron (npm) versions < 39.8.1 is affected.
4. Is there a fix for CVE-2026-34774? Yes. CVE-2026-34774 is fixed in 39.8.1, 40.7.0, 41.0.0. Upgrade to this version or later.
5. Is CVE-2026-34774 exploitable, and should I be worried? Whether CVE-2026-34774 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-2026-34774 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-2026-34774?
   • Upgrade electron to 39.8.1 or later
   • Upgrade electron to 40.7.0 or later
   • Upgrade electron to 41.0.0 or later