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Fencer Intel
high 7.4

CVE-2026-70604 json

Electron: Custom protocol with supportFetchAPI but not corsEnabled allows cross-origin reads

published 3mo ago modified last mo. also EUVD-2026-53440 , GHSA-v3j7-r9gq-3gjw

cvss
7.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits
0
none known

Summary

Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to 39.8.10, 40.9.3, 41.4.0, and 42.0.0, a 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. Apps that serve sensitive data from such a scheme and load remote or untrusted content in a renderer are affected. This issue is fixed in versions 39.8.10, 40.9.3, 41.4.0, and 42.0.0.

Patch / fix

  • npm electron 39.8.10, 40.9.3, 41.4.0, 42.0.0
  • atom electron 39.8.10, 40.9.3, 41.4.0, 42.0.0
  • electronjs electron 39.8.10, 40.9.3, 41.4.0, 42.0.0

Is CVE-2026-70604 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3mo ago

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 7.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N
GitHub 3.1 7.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
npm electron
>=42.0.0-alpha.1, <42.0.0
>=41.0.0-alpha.1, <41.4.0
>=40.0.0-alpha.1, <40.9.3
<39.8.10
42.0.0
41.4.0
40.9.3
39.8.10

Affected products

  • electron electron

Classification

Weakness
  • CWE-942 Permissive Cross-domain Security Policy with Untrusted Domains

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of electron/electron published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.