CVE-2026-34778
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 · uneditedElectron 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, a service worker running in a session could spoof reply messages on the internal IPC channel used by webContents.executeJavaScript() and related methods, causing the main-process promise to resolve with attacker-controlled data. Apps are only affected if they have service workers registered and use the result of webContents.executeJavaScript() (or webFrameMain.executeJavaScript()) in security-sensitive decisions. 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 confidenceIn Electron prior to versions 38.8.6/39.8.1/40.8.1/41.0.0, a service worker running in a session can spoof reply messages on the internal IPC channel used by webContents.executeJavaScript() and webFrameMain.executeJavaScript(), causing the main-process promise to resolve with attacker-controlled data instead of actual execution results.
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< 38.8.6>= 39.0.0, < 39.8.1>= 40.0.0, < 40.8.1= 41.0.0CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/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 checksWork through these to decide whether this CVE applies to you.
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Identify Electron versionRun `console.log(process.versions.electron)` in the app, or check package.json for electron version, or run `electron --version` from command lineAffected if Installed version is < 38.8.6, or >= 39.0.0 and < 39.8.1, or >= 40.0.0 and < 40.8.1, or exactly 41.0.0
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Confirm use of webContents.executeJavaScriptSearch codebase for calls to webContents.executeJavaScript, webContents.executeCode, or similar methods that run scripts in renderer and return results to main processAffected if Codebase uses executeJavaScript or related methods that return results to the main process via IPC
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Check for service worker registrationSearch application code and loaded scripts for ServiceWorkerContainer.register() calls or service worker script registration in any renderer processAffected if Any renderer context registers or uses service workers (including third-party scripts)
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Inspect Node integration settingsCheck BrowserWindow webPreferences for nodeIntegration, contextIsolation, and sandbox settingsAffected if Service workers can run in the same session where executeJavaScript is used (vulnerability requires service worker in the same session as the vulnerable executeJavaScript call)
Environment is affected if running a vulnerable Electron version AND using executeJavaScript in a session that also has active service workers.
Generated from the published advisory. Verify against your own configuration.
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 · scoped38.8.639.8.140.8.1
Update Electron to version 38.8.6, 39.8.1, 40.8.1, or 41.0.0 or later. Additionally, audit code that uses executeJavaScript results in security-sensitive contexts and avoid trusting those results if service workers are registered.
Upgrade to Electron 38.8.6, 39.8.1, 40.8.1, or 41.0.0 depending on your current major version
- 1. Identify the current Electron version in your project by running `npm list electron` or checking package.json
- 2. Determine the appropriate upgrade version based on your 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 version in package.json: `npm install electron@<fixed-version> --save-dev` or edit package.json manually
- 4. Run `npm install` or `yarn install` to update the dependency
- 5. If your app uses native modules, rebuild them for the new Electron version using electron-rebuild or by running `npm run rebuild`
- 6. Test that webContents.executeJavaScript() and webFrameMain.executeJavaScript() behave correctly, especially if your app uses service workers
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-34778 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-34778 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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