CVE-2026-70606

Electron: ProtocolResponse.url reuses the default session cache instead of the registering session

Workarounds

Set ProtocolResponse.session explicitly so the request uses the intended session's cache.

Fixed Versions

• 43.0.0
• 42.5.1
• 41.9.1
• 40.10.6

For more information

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

When a custom protocol handler returned a ProtocolResponse with a url and no session, Electron made the upstream request through defaultSession instead of the session that handled the protocol. A cached response could then be reused across otherwise isolated session partitions.

Apps that use ProtocolResponse.url, omit ProtocolResponse.session, and rely on separate sessions to isolate content are affected. Apps that set an explicit session, or that do not isolate content across sessions, are not affected.

CVE-2026-70606 has a CVSS score of 5.9 (Medium). The vector is network-reachable, no privileges required, and user interaction required. 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 (43.0.0, 42.5.1, 41.9.1, 40.10.6); upgrading removes the vulnerable code path.

Kodem intelligence

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1. What is CVE-2026-70606? CVE-2026-70606 is a medium-severity security vulnerability in electron (npm), affecting versions >= 43.0.0-alpha.1, < 43.0.0. It is fixed in 43.0.0, 42.5.1, 41.9.1, 40.10.6.
2. How severe is CVE-2026-70606? CVE-2026-70606 has a CVSS score of 5.9 (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-2026-70606? electron (npm) versions >= 43.0.0-alpha.1, < 43.0.0 is affected.
4. Is there a fix for CVE-2026-70606? Yes. CVE-2026-70606 is fixed in 43.0.0, 42.5.1, 41.9.1, 40.10.6. Upgrade to this version or later.
5. Is CVE-2026-70606 exploitable, and should I be worried? Whether CVE-2026-70606 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-2026-70606 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-2026-70606?
   • Upgrade electron to 43.0.0 or later
   • Upgrade electron to 42.5.1 or later
   • Upgrade electron to 41.9.1 or later
   • Upgrade electron to 40.10.6 or later

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