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Electron: Sandboxed iframes can launch external protocol handlers

Moderate severity GitHub Reviewed Published Jul 27, 2026 in electron/electron • Updated Aug 5, 2026

Package

npm electron (npm)

Affected versions

< 39.8.8
>= 40.0.0-alpha.1, < 40.9.0
>= 41.0.0-alpha.1, < 41.2.1
>= 42.0.0-alpha.1, < 42.0.0-beta.3

Patched versions

39.8.8
40.9.0
41.2.1
42.0.0-beta.3

Description

Impact

Requests to open external protocol URLs from web content did not take iframe sandbox restrictions into account, so a sandboxed iframe could cause an OS-registered external application to be launched. The frame's sandbox state was also not made available to the app's permission handlers.

Apps are only affected if they render untrusted content in sandboxed iframes and grant the openExternal permission (granted by default when no setPermissionRequestHandler is installed). Apps whose permission handler denies openExternal for untrusted content are not affected.

Workarounds

Install a setPermissionRequestHandler that denies the openExternal permission for untrusted content.

Fixed Versions

  • 42.0.0-beta.3
  • 41.2.1
  • 40.9.0
  • 39.8.8

For more information

If you have any questions or comments about this advisory, email Electron at security@electronjs.org

References

@MarshallOfSound MarshallOfSound published to electron/electron Jul 27, 2026
Published to the GitHub Advisory Database Aug 5, 2026
Reviewed Aug 5, 2026
Last updated Aug 5, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(29th percentile)

Weaknesses

Improper Access Control

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. Learn more on MITRE.

CVE ID

CVE-2026-70612

GHSA ID

GHSA-p2rr-rvmm-c5fp

Source code

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