CVE-2026-70606: Electron ProtocolResponse.url Reuses The Default Session Vulnerability

MODERATE
Advisory Identifier: GHSA-r4w5-6pfg-jxp5
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CVSS 5.9
CWE-668
Published
Advisory Summary

CVE-2026-70606 is a MODERATE (CVSS 5.9) protocolresponse.url reuses the default session vulnerability (CWE-668: Exposure of Resource to Wrong Sphere) affecting Electron libraries in the npm ecosystem. The issue involves protocolresponse.url reuses the default session cache instead of the registering session. Remediation is available by upgrading affected packages to version 43.0.0, 42.5.1, 41.9.1, 40.10.6.

CVE-2026-70606 at a Glance

CVE Identifier CVE-2026-70606
GHSA Identifier GHSA-r4w5-6pfg-jxp5
Severity MODERATE
CVSS v3.1 Base Score 5.9
CWE Classification CWE-668: Exposure of Resource to Wrong Sphere
Affected Product Electron
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 5.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-70606

To remediate this vulnerability, upgrade all affected Electron dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

electron fixed: 43.0.0 
npm install electron@43.0.0
electron fixed: 42.5.1 
npm install electron@42.5.1
electron fixed: 41.9.1 
npm install electron@41.9.1
electron fixed: 40.10.6 
npm install electron@40.10.6
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls electron

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-70606, inspect your project dependencies using npm:

npm ls electron

Analyze the terminal output to locate any version of Electron in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 43.0.0), your application is affected.

Note: The npm ls electron command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-668: Exposure of Resource to Wrong Sphere, where the product exposes a resource to the wrong control sphere, providing unintended actors with inappropriate access to the resource. In Electron, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact When a custom protocol handler returned a `ProtocolResponse` with a `url` and no `session`, Electron made the upstream request through `defaultSession` instead of the session that handled the protocol. A cached response could then be reused across otherwise isolated session partitions. Apps that use `ProtocolResponse.url`, omit `ProtocolResponse.session`, and rely on separate sessions to isolate content are affected. Apps that set an explicit `session`, or that do not isolate content across sessions, are not affected. ### Workarounds Set `ProtocolResponse.session` explicitly so the request uses the intended session's cache. ### Fixed Versions * `43.0.0` * `42.5.1` * `41.9.1` * `40.10.6` ### For more information If you have any questions or comments about this advisory, email Electron at [security@electronjs.org](mailto:security@electronjs.org)

CVE-2026-70606 Affected Electron Versions

4 component(s)
Fixed Versions:
43.0.042.5.141.9.140.10.6
Product / Package Ecosystem Affected Versions Fixed Version
electron
npm/electron
npm
≥ 43.0.0-alpha.1
< 43.0.0
43.0.0
electron
npm/electron
npm
≥ 42.0.0-alpha.1
< 42.5.1
42.5.1
electron
npm/electron
npm
≥ 41.0.0-alpha.1
< 41.9.1
41.9.1
electron
npm/electron
npm
≥ 40.0.0-alpha.1
< 40.10.6
40.10.6

References

GitHub Advisory / Wiki ADVISORY
https://github.com/electron/electron/security/advisories/GHSA-r4w5-6pfg-jxp5
Electron Source Repository REPOSITORY
https://github.com/electron/electron

Frequently Asked Questions

What is CVE-2026-70606?
CVE-2026-70606 is a security vulnerability in Electron involving ProtocolResponse.url reuses the default session cache instead of the registering session under CWE-668: Exposure of Resource to Wrong Sphere.
Which Electron versions are affected?
Affected versions include releases prior to 43.0.0, 42.5.1, 41.9.1, 40.10.6 across affected packages: electron.
What version fixes CVE-2026-70606?
Upgrading to 43.0.0, 42.5.1, 41.9.1, 40.10.6 (or the latest patched release for your respective branch) resolves the vulnerability.
Is electron affected?
Yes, electron is affected in releases prior to 43.0.0, 42.5.1, 41.9.1, 40.10.6. Upgrade your dependency to 43.0.0, 42.5.1, 41.9.1, 40.10.6 or later.
What is the CVSS score of CVE-2026-70606?
CVE-2026-70606 has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N.
What CWE is associated with CVE-2026-70606?
CVE-2026-70606 is classified under CWE-668: Exposure of Resource to Wrong Sphere (The product exposes a resource to the wrong control sphere, providing unintended actors with inappropriate access to the resource.).
How can I check npm dependencies for CVE-2026-70606?
Run the dependency tree command: 'npm ls electron'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-r4w5-6pfg-jxp5",
  "modified" : "2026-08-05T16:07:59Z",
  "published" : "2026-08-05T16:07:59Z",
  "aliases" : [ "CVE-2026-70606" ],
  "summary" : "Electron: ProtocolResponse.url reuses the default session cache instead of the registering session",
  "details" : "### Impact\nWhen a custom protocol handler returned a `ProtocolResponse` with a `url` and no `session`, Electron made the upstream request through `defaultSession` instead of the session that handled the protocol. A cached response could then be reused across otherwise isolated session partitions.\n\nApps that use `ProtocolResponse.url`, omit `ProtocolResponse.session`, and rely on separate sessions to isolate content are affected. Apps that set an explicit `session`, or that do not isolate content across sessions, are not affected.\n\n### Workarounds\nSet `ProtocolResponse.session` explicitly so the request uses the intended session's cache.\n\n### Fixed Versions\n* `43.0.0`\n* `42.5.1`\n* `41.9.1`\n* `40.10.6`\n\n### For more information\nIf you have any questions or comments about this advisory, email Electron at [security@electronjs.org](mailto:security@electronjs.org)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N"
  } ],
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  "references" : [ {
    "type" : "WEB",
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  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/electron/electron"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-668" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-05T16:07:59Z",
    "nvd_published_at" : null
  }
}