Electron: shell.openPath path validation bypass via embedded null byte

Exploitation

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

CVSS

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

EPSS

• CVE-2026-70603: 0.13% estimated exploitation activity in the next 30 days; percentile 2.81 (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 shell.openPath() did not reject paths containing embedded null bytes. Apps that perform string-only validation of file paths (for example, checking the file extension) before passing them to shell.openPath() could be bypassed, allowing an attacker-controlled path to open a different file than the one that passed validation. Apps are only affected if they pass paths derived from untrusted input to shell.openPath() and rely on string-based validation without a filesystem check. Node's fs APIs already reject paths containing null bytes, so apps that call fs.existsSync(), fs.stat(), or similar before shell.openPath() are not affected. Apps that do not call shell.openPath() with untrusted input are not affected. Workarounds Reject any path containing a null byte before passing it to shell.openPath(): Fixed Versions 42.0.0-beta.1 41.1.1 40.9.0 39.8.6 For more information If you have any questions or comments about this advisory, email us at security@electronjs.org

Published by the source

5 Aug 2026, 15:57 UTC

Last modified by the source

5 Aug 2026, 15:57 UTC

Source last checked

26 Oct 2026, 13:00 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-5c9j-mhmv-5xgx

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# Patch Next advisory brief: CVE-2026-70603

Advisory: Electron: shell.openPath path validation bypass via embedded null byte
IDs: CVE-2026-70603, GHSA-5c9j-mhmv-5xgx
Record: https://patchnext.com/advisories/cve-2026-70603 (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 6.0)
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.1, 41.1.1, 40.9.0, 39.8.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm electron: affected >= 42.0.0-alpha.1, < 42.0.0-beta.1; >= 41.0.0-alpha.1, < 41.1.1; >= 40.0.0-alpha.1, < 40.9.0; < 39.8.6; fixed in 39.8.6, 41.1.1, 42.0.0-beta.1, 40.9.0

## 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-5c9j-mhmv-5xgx (GitHub-reviewed advisory GHSA-5c9j-mhmv-5xgx lists affected ranges: npm electron >=42.0.0-alpha.1 =41.0.0-alpha.1 =40.0.0-alpha.1 =0 <39.8.6)

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