Out-of-bounds Read in Electron
CVE-2026-34776
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, on macOS and Linux, apps that call app.requestSingleInstanceLock() were vulnerable to an out-of-bounds heap read when parsing a crafted second-instance message. Leaked memory could be delivered to the app's second-instance event handler. This issue is limited to processes running as the same user as the Electron app. Apps that do not call app.requestSingleInstanceLock() are not affected. Windows is not affected by this issue. This issue has been patched in versions 38.8.6, 39.8.1, 40.8.1, and 41.0.0.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:L.
EPSS exploit prediction
EPSS: 0.002 (12.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 13th percentile — 12.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · 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-3c8v-cfp5-9885 (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-34776?
- CVE-2026-34776 is a medium-severity vulnerability in Electron, classified under Out-of-bounds Read. CVSS score: 5.3/10. Published 2026-04-04.
- How severe is CVE-2026-34776?
- Medium severity. CVSS v3 base score is 5.3 out of 10.