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GHSA-mwmh-mq4g-g6gr

MEDIUM

GHSA-mwmh-mq4g-g6gr is a medium-severity (CVSS 4.7) Improper Input Validation vulnerability in electron. O3 Security confirms whether GHSA-mwmh-mq4g-g6gr is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

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

Also known asCVE-2026-34773
Published
Apr 3, 2026
Updated
Apr 6, 2026
Affected
4 pkgs
Patched
4 / 4
Exploits
None indexed

Blast Radius

4 pkgs affected

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

electronnpm
5.8Mdownloads / week

Description

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 [email protected]

Affected Packages

4 total 4 fixed
EcosystemPackageVulnerable rangeFix
📦npmelectronall versions38.8.6
📦npmelectron39.0.0-alpha.1&&< 39.8.139.8.1
📦npmelectron40.0.0-alpha.1&&< 40.8.140.8.1
📦npmelectron41.0.0-alpha.1&&< 41.0.041.0.0

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for electron. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update electron to 38.8.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mwmh-mq4g-g6gr is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-mwmh-mq4g-g6gr is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-mwmh-mq4g-g6gr. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### 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
O3 Security · Impact-Aware SCA

Is GHSA-mwmh-mq4g-g6gr in your dependencies?

O3 detects GHSA-mwmh-mq4g-g6gr across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.