# CVE-2026-70606: Electron cache isolation bypass in ProtocolResponse

Source: https://junglewise.ai/threats/cve-2026-70606-electron-cache-isolation-bypass-in-protocolresponse  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-05. Updated: 2026-08-05  
License: CC BY 4.0 with a link back

CVE-2026-70606 · Severity: medium · CVSS 5.9 · Published 2026-08-05

Electron is a framework used to build desktop applications like Slack, Discord, and VS Code. A flaw in how it handles custom network protocols could allow data from one user session to be accidentally shared with or reused by another session. This could lead to a breach of privacy or data isolation in applications that rely on separate sessions to keep user data partitioned.

Technologies: [electron (npm)](https://junglewise.ai/threats/technologies/electron). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-70606 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-70606 being exploited in the wild.

**How severe is CVE-2026-70606?** Medium severity, with a CVSS score of 5.9, published 5 August 2026.

**Which products and versions are affected?** electron (npm) SEMVER:introduced=43.0.0-alpha.1,fixed=43.0.0.

**Is there a fix for CVE-2026-70606?** Yes. electron (npm): upgrade to 43.0.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-70606 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-70606?** Check whether you run electron (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- electron (npm): upgrade to 43.0.0 or later

  ```sh
  npm install electron@43.0.0
  ```


## Technical details

A vulnerability exists in Electron's custom protocol handling mechanism (CWE-668). When a custom protocol handler returns a ProtocolResponse containing a 'url' but omits the 'session' property, Electron incorrectly defaults to using the 'defaultSession' for the upstream request. This behavior allows cached responses to be shared across session partitions that were intended to be isolated. Attackers could potentially exploit this to access sensitive cached data from a different session context. The issue is fixed in versions 43.0.0, 42.5.1, 41.9.1, and 40.10.6. Developers can work around this by explicitly setting the 'session' property in ProtocolResponse.

## Affected products

- Electron electron >= 43.0.0-alpha.1, < 43.0.0; >= 42.0.0-alpha.1, < 42.5.1; >= 41.0.0-alpha.1, < 41.9.1; >= 40.0.0-alpha.1, < 40.10.6

## Identifiers

- CVE-2026-70606
- GHSA-r4w5-6pfg-jxp5

## Timeline

- 2026-07-27: disclosed
- 2026-08-05: advisory: GitHub Advisory published
- 2026-08-05: patched

## References

- [https://api.github.com/users/rushitgit](https://api.github.com/users/rushitgit)
- [https://github.com/rushitgit](https://github.com/rushitgit)
- [https://api.github.com/users/rushitgit/gists%7B/gist_id%7D](https://api.github.com/users/rushitgit/gists%7B/gist_id%7D)
- [https://api.github.com/users/rushitgit/repos](https://api.github.com/users/rushitgit/repos)
- [https://avatars.githubusercontent.com/u/95172033?v=4](https://avatars.githubusercontent.com/u/95172033?v=4)
- [https://api.github.com/users/rushitgit/events%7B/privacy%7D](https://api.github.com/users/rushitgit/events%7B/privacy%7D)

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- [Electron external protocol permission misattribution](https://junglewise.ai/threats/cve-2026-114121-electron-is-a-framework-for-writing-cross-platform-desktop)
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