Electron: Registry key path injection in app.setAsDefaultProtocolClient on Windows

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

4.7 · CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N

EPSS

• CVE-2026-34773: 0.24% estimated exploitation activity in the next 30 days; percentile 15.71 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact On Windows, app.setAsDefaultProtocolClient(protocol) did not validate the protocol name before writing to the registry. Apps that pass untrusted input as the protocol name may allow an attacker to write to arbitrary subkeys under HKCU\Software\Classes\, potentially hijacking existing protocol handlers. Apps are only affected if they call app.setAsDefaultProtocolClient() with a protocol name derived from external or untrusted input. Apps that use a hardcoded protocol name are not affected. Workarounds Validate the protocol name matches /^[a-zA-Z][a-zA-Z0-9+.-]$/ before passing it to app.setAsDefaultProtocolClient(). Fixed Versions 41.0.0 40.8.1 39.8.1 38.8.6 For more information If there are any questions or comments about this advisory, please email security@electronjs.org

Published by the source

3 Apr 2026, 02:41 UTC

Last modified by the source

6 Apr 2026, 23:18 UTC

Source last checked

26 Oct 2026, 12:47 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-mwmh-mq4g-g6gr

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-mwmh-mq4g-g6gr

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# Patch Next advisory brief: CVE-2026-34773

Advisory: Electron: Registry key path injection in app.setAsDefaultProtocolClient on Windows
IDs: CVE-2026-34773, GHSA-mwmh-mq4g-g6gr
Record: https://patchnext.com/advisories/cve-2026-34773 (revision 2, source checked 26 Oct 2026, 12:47 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: electron 41.0.0, 40.8.1, 39.8.1, 38.8.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm electron: affected < 38.8.6; >= 39.0.0-alpha.1, < 39.8.1; >= 40.0.0-alpha.1, < 40.8.1; >= 41.0.0-alpha.1, < 41.0.0; fixed in 41.0.0, 38.8.6, 40.8.1, 39.8.1

## 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://osv.dev/vulnerability/GHSA-mwmh-mq4g-g6gr (OSV record GHSA-mwmh-mq4g-g6gr lists affected ranges: npm electron >=0 =39.0.0-alpha.1 =40.0.0-alpha.1 =41.0.0-alpha.1 <41.0.0 (fixed))
- Verified: https://github.com/advisories/GHSA-mwmh-mq4g-g6gr (GitHub-reviewed advisory GHSA-mwmh-mq4g-g6gr lists affected ranges: npm electron >=0 =39.0.0-alpha.1 =40.0.0-alpha.1 =41.0.0-alpha.1 <41.0.0)

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