Vulnerability in Electron
CVE-2026-34778
Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to versions 38.8.6, 39.8.1, 40.8.1, and 41.0.0, 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. This issue has been patched in versions 38.8.6, 39.8.1, 40.8.1, and 41.0.0.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N.
EPSS exploit prediction
EPSS: 0.001 (2.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 3rd percentile — 2.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: +0.000
Affected products
- Electron — versions < 38.8.6, >= 39.0.0-alpha.1, < 39.8.1, >= 40.0.0-alpha.1, < 40.8.1
- Electronjs Electron — versions 41.0.0
Weakness classification (CWE)
References
- github.com/electron/electron/security/advisories/GHSA-xj5x-m3f3-5x3h (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-34778?
- CVE-2026-34778 is a medium-severity vulnerability in Electron, classified under Authentication Bypass by Spoofing. CVSS score: 5.9/10. Published 2026-04-04.
- How severe is CVE-2026-34778?
- Medium severity. CVSS v3 base score is 5.9 out of 10.