CVE-2026-70604: Electron Custom Protocol With SupportFetchAPI But Vulnerability
HIGHCVE-2026-70604 is a HIGH (CVSS 7.4) custom protocol with supportfetchapi but vulnerability (CWE-942: Permissive Cross-domain Security Policy with Untrusted Domains) affecting Electron libraries in the npm ecosystem. The issue involves custom protocol with supportfetchapi but not corsenabled allows cross-origin reads. Remediation is available by upgrading affected packages to version 42.0.0, 41.4.0, 40.9.3, 39.8.10.
CVE-2026-70604 at a Glance
Security Impact
CVSS: 7.4
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N).
How to Fix CVE-2026-70604
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.
npm install electron@42.0.0npm install electron@41.4.0npm install electron@40.9.3npm install electron@39.8.10Run the following command in your project directory to verify that all resolved dependencies use the patched release:
npm ls electronHow to Check if You Are Affected
To determine whether your Node.js application is affected by CVE-2026-70604, inspect your project dependencies using npm:
npm ls electronAnalyze 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 42.0.0), 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-942: Permissive Cross-domain Security Policy with Untrusted Domains, where the product uses a web-client protection mechanism such as a content security policy (csp) or cross-domain policy file, but the policy includes untrusted domains with which the web client is allowed to communicate. 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
CVE-2026-70604 Affected Electron Versions
4 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
electron
|
npm |
≥ 42.0.0-alpha.1
< 42.0.0
|
42.0.0
|
|
electron
|
npm |
≥ 41.0.0-alpha.1
< 41.4.0
|
41.4.0
|
|
electron
|
npm |
≥ 40.0.0-alpha.1
< 40.9.3
|
40.9.3
|
|
electron
|
npm |
< 39.8.10
|
39.8.10
|
References
Frequently Asked Questions
What is CVE-2026-70604?
Which Electron versions are affected?
What version fixes CVE-2026-70604?
Is electron affected?
What is the CVSS score of CVE-2026-70604?
What CWE is associated with CVE-2026-70604?
How can I check npm dependencies for CVE-2026-70604?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-v3j7-r9gq-3gjw",
"modified" : "2026-08-05T15:59:45Z",
"published" : "2026-08-05T15:59:45Z",
"aliases" : [ "CVE-2026-70604" ],
"summary" : "Electron: Custom protocol with supportFetchAPI but not corsEnabled allows cross-origin reads",
"details" : "### Impact\nA custom scheme registered with `supportFetchAPI: true` but without `corsEnabled: true` was not subject to CORS enforcement. A page loaded from a remote origin could therefore `fetch()` or `XMLHttpRequest` that scheme cross-origin and read the full response body, rather than the read being blocked.\n\nApps that serve sensitive data from such a scheme and load remote or untrusted content in a renderer are affected. Apps that set `corsEnabled: true`, or that do not load untrusted content, are not affected.\n\n### Workarounds\nSet `corsEnabled: true` on schemes that must enforce CORS, and validate the request `Origin` in your protocol handler before returning sensitive data.\n\n### Fixed Versions\n* `42.0.0`\n* `41.4.0`\n* `40.9.3`\n* `39.8.10`\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:L/PR:N/UI:R/S:C/C:H/I:N/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "npm",
"name" : "electron"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "42.0.0-alpha.1"
}, {
"fixed" : "42.0.0"
} ]
} ]
}, {
"package" : {
"ecosystem" : "npm",
"name" : "electron"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "41.0.0-alpha.1"
}, {
"fixed" : "41.4.0"
} ]
} ]
}, {
"package" : {
"ecosystem" : "npm",
"name" : "electron"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "40.0.0-alpha.1"
}, {
"fixed" : "40.9.3"
} ]
} ]
}, {
"package" : {
"ecosystem" : "npm",
"name" : "electron"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "39.8.10"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/electron/electron/security/advisories/GHSA-v3j7-r9gq-3gjw"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/electron/electron"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-942" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2026-08-05T15:59:45Z",
"nvd_published_at" : null
}
}