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ElectronApplication · Electronjs

CVE-2026-34776

MEDIUM · 5.3 CVSS v3.1 Published 2026-04-04
Fix available
A fix is available. Upgrade to 38.8.6 / 39.8.1 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to versions 38.8.6, 39.8.1, 40.8.1, and 41.0.0, 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. This issue has been patched in versions 38.8.6, 39.8.1, 40.8.1, and 41.0.0.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In Electron apps on macOS and Linux that use app.requestSingleInstanceLock(), a crafted second-instance message triggers an out-of-bounds heap read, allowing leaking arbitrary heap memory to the application's second-instance event handler. This only affects same-user processes and Windows is not impacted.

MitigationUpdate Electron to versions 38.8.6, 39.8.1, 40.8.1, or 41.0.0 to patch the vulnerability. If immediate patching is not feasible, avoid using app.requestSingleInstanceLock() until upgrade is possible.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
ElectronApplication
Affected:< 38.8.6>= 39.0.0, < 39.8.1>= 40.0.0, < 40.8.1= 41.0.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Electron version
    Run 'npm list electron' or check the electron version in package.json, or run 'electron --version' from the application directory
    Affected if version is less than 38.8.6, or between 39.0.0 and 39.8.1 (exclusive), or between 40.0.0 and 40.8.1 (exclusive), or exactly 41.0.0
  2. Verify single instance lock is used
    Search the application source code for 'app.requestSingleInstanceLock()' calls
    Affected if the application calls app.requestSingleInstanceLock() to enforce single-instance behavior
  3. Confirm operating system
    Check if the application is running on macOS or Linux (check via 'uname -a' or system info)
    Affected if running on macOS or Linux; the vulnerability does not affect Windows

Affected if: Electron version is in a vulnerable range AND the app uses app.requestSingleInstanceLock() AND runs on macOS or Linux.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 38.8.6 / 39.8.1 / 40.8.1 or later
Fixed in 38.8.639.8.140.8.1
Interim mitigation

Update Electron to versions 38.8.6, 39.8.1, 40.8.1, or 41.0.0 to patch the vulnerability. If immediate patching is not feasible, avoid using app.requestSingleInstanceLock() until upgrade is possible.

Recommended fix High confidence

Upgrade to Electron 38.8.6, 39.8.1, 40.8.1, or 41.0.0 (41.0.0 recommended for latest features and fixes)

  1. Identify the current Electron version in use by checking package.json or node_modules/electron/package.json
  2. Determine the appropriate target version based on current version: if <38.8.6 upgrade to 38.8.6; if >=39.0.0 and <39.8.1 upgrade to 39.8.1; if >=40.0.0 and <40.8.1 upgrade to 40.8.1; if 41.0.0 upgrade to 41.0.0
  3. Update the Electron dependency in package.json to the appropriate fixed version (e.g., "electron": "^41.0.0")
  4. Run npm install or yarn install to download the updated Electron version
  5. Verify the installation by checking electron --version
  6. Test the application's second-instance lock functionality to ensure it works correctly
  7. If running on macOS or Linux, ensure app.requestSingleInstanceLock() behaves as expected after upgrade
  8. Rebuild and redistribute the application with the patched Electron version
Caveat Major Electron upgrades may include breaking API changes; review Electron changelog before upgrading and test thoroughly

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Electron Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-34776 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data