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Medium, CVSS 5.4

Electron: contextBridge object copy honors prototype setters

CVE-2026-70610GHSA-ff2p-hmqr-hxm4

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (electron 42.0.0-beta.4, 41.2.2, 40.9.2, 39.8.9), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • npm electron

    Affected
    < 39.8.9>= 40.0.0-alpha.1, < 40.9.2>= 41.0.0-alpha.1, < 41.2.2>= 42.0.0-alpha.1, < 42.0.0-beta.4
    Fixed in
    39.8.9, 40.9.2, 42.0.0-beta.4, 41.2.2

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
5.4 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
EPSS
  • CVE-2026-70610: 0.56% estimated exploitation activity in the next 30 days; percentile 46.89 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Impact Objects copied across the contextBridge boundary from untrusted content could carry an attacker-influenced prototype, enabling prototype-pollution-style attacks against preload code despite context isolation being enabled. Apps are only affected if their preload code accepts object arguments from untrusted content and reads properties from them without own-property checks. Apps that only accept primitive arguments, or that validate object arguments, are not affected. Workarounds Validate objects received from untrusted content with own-property checks (Object.hasOwn), or copy them onto a null-prototype object before use. Fixed Versions 42.0.0-beta.4 41.2.2 40.9.2 39.8.9 For more information If you have any questions or comments about this advisory, email Electron at security@electronjs.org

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 1 · created ·

    Published from ghsa record GHSA-ff2p-hmqr-hxm4

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-70610

Advisory: Electron: contextBridge object copy honors prototype setters
IDs: CVE-2026-70610, GHSA-ff2p-hmqr-hxm4
Record: https://patchnext.com/advisories/cve-2026-70610 (revision 1, source checked 26 Oct 2026, 13:00 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: electron 42.0.0-beta.4, 41.2.2, 40.9.2, 39.8.9. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm electron: affected < 39.8.9; >= 40.0.0-alpha.1, < 40.9.2; >= 41.0.0-alpha.1, < 41.2.2; >= 42.0.0-alpha.1, < 42.0.0-beta.4; fixed in 39.8.9, 40.9.2, 42.0.0-beta.4, 41.2.2

## Suggested inspection (read-only)
- `npm ls electron --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on electron.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-ff2p-hmqr-hxm4 (GitHub-reviewed advisory GHSA-ff2p-hmqr-hxm4 lists affected ranges: npm electron >=0 =40.0.0-alpha.1 =41.0.0-alpha.1 =42.0.0-alpha.1 <42.0.0-beta.4)

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