Electron: Out-of-bounds read in second-instance IPC on macOS and Linux

Exploitation

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

CVSS

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

EPSS

• CVE-2026-34776: 0.22% estimated exploitation activity in the next 30 days; percentile 12.99 (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 macOS and Linux, apps that call app.requestSingleInstanceLock() were vulnerable to an out-of-bounds heap read when parsing a crafted second-instance message. Leaked memory could be delivered to the app's second-instance event handler. This issue is limited to processes running as the same user as the Electron app. Apps that do not call app.requestSingleInstanceLock() are not affected. Windows is not affected by this issue. Workarounds There are no app side workarounds, developers must update to a patched version of Electron. 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, 02:43 UTC

Last modified by the source

6 Apr 2026, 23:20 UTC

Source last checked

26 Oct 2026, 12:47 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-3c8v-cfp5-9885

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-3c8v-cfp5-9885

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# Patch Next advisory brief: CVE-2026-34776

Advisory: Electron: Out-of-bounds read in second-instance IPC on macOS and Linux
IDs: CVE-2026-34776, GHSA-3c8v-cfp5-9885
Record: https://patchnext.com/advisories/cve-2026-34776 (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 5.3)
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-3c8v-cfp5-9885 (OSV record GHSA-3c8v-cfp5-9885 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-3c8v-cfp5-9885 (GitHub-reviewed advisory GHSA-3c8v-cfp5-9885 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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