What is CVE-2026-34778?

CVE-2026-34778 is a medium-severity security vulnerability in electron (npm), affecting versions < 38.8.6. It is fixed in 38.8.6, 39.8.1, 40.8.1, 41.0.0.

How severe is CVE-2026-34778?

CVE-2026-34778 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.

Which versions of electron are affected by CVE-2026-34778?

electron (npm) versions < 38.8.6 is affected.

Is there a fix for CVE-2026-34778?

Yes. CVE-2026-34778 is fixed in 38.8.6, 39.8.1, 40.8.1, 41.0.0. Upgrade to this version or later.

Is CVE-2026-34778 exploitable, and should I be worried?

Whether CVE-2026-34778 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.

What actually determines whether CVE-2026-34778 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.

CVE-2026-34778 in electron | Intelligent Application Security

Q: How severe is CVE-2026-34778?

CVE-2026-34778 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.

Q: Which versions of electron are affected by CVE-2026-34778?

electron (npm) versions < 38.8.6 is affected.

Q: Is there a fix for CVE-2026-34778?

Yes. CVE-2026-34778 is fixed in 38.8.6, 39.8.1, 40.8.1, 41.0.0. Upgrade to this version or later.

Q: Is CVE-2026-34778 exploitable, and should I be worried?

Whether CVE-2026-34778 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.

Q: What actually determines whether CVE-2026-34778 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.

Q: How do I fix CVE-2026-34778?

Upgrade: electron to 38.8.6 or later, electron to 39.8.1 or later, electron to 40.8.1 or later, electron to 41.0.0 or later.

Summary

Workarounds

Do not trust the return value of webContents.executeJavaScript() for security decisions. Use dedicated, validated IPC channels for security-relevant communication with renderers.

Fixed Versions

41.0.0
40.8.1
39.8.1
38.8.6

For more information

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

Impact

A service worker running in a session could spoof reply messages on the internal IPC channel used by webContents.executeJavaScript() and related methods, causing the main-process promise to resolve with attacker-controlled data.

Apps are only affected if they have service workers registered and use the result of webContents.executeJavaScript() (or webFrameMain.executeJavaScript()) in security-sensitive decisions.

CVE-2026-34778 has a CVSS score of 5.9 (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 (38.8.6, 39.8.1, 40.8.1, 41.0.0); upgrading removes the vulnerable code path.

Affected versions

electron (< 38.8.6) electron (>= 39.0.0-alpha.1, < 39.8.1) electron (>= 40.0.0-alpha.1, < 40.8.1) electron (>= 41.0.0-alpha.1, < 41.0.0)

Security releases

electron → 38.8.6 (npm) electron → 39.8.1 (npm) electron → 40.8.1 (npm) electron → 41.0.0 (npm)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

See it in your environment

Remediation advice

Upgrade the following packages to resolve this vulnerability:

electron to 38.8.6 or later; electron to 39.8.1 or later; electron to 40.8.1 or later; electron to 41.0.0 or later

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

What is CVE-2026-34778? CVE-2026-34778 is a medium-severity security vulnerability in electron (npm), affecting versions < 38.8.6. It is fixed in 38.8.6, 39.8.1, 40.8.1, 41.0.0.
How severe is CVE-2026-34778? CVE-2026-34778 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.
Which versions of electron are affected by CVE-2026-34778? electron (npm) versions < 38.8.6 is affected.
Is there a fix for CVE-2026-34778? Yes. CVE-2026-34778 is fixed in 38.8.6, 39.8.1, 40.8.1, 41.0.0. Upgrade to this version or later.
Is CVE-2026-34778 exploitable, and should I be worried? Whether CVE-2026-34778 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
What actually determines whether CVE-2026-34778 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.
How do I fix CVE-2026-34778?
- Upgrade electron to 38.8.6 or later
- Upgrade electron to 39.8.1 or later
- Upgrade electron to 40.8.1 or later
- Upgrade electron to 41.0.0 or later

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CVE-2026-54257 CVE-2026-34781 CVE-2026-34765 CVE-2026-34764 CVE-2026-34780