CVE-2026-34777
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, when an iframe requests fullscreen, pointerLock, keyboardLock, openExternal, or media permissions, the origin passed to session.setPermissionRequestHandler() was the top-level page's origin rather than the requesting iframe's origin. Apps that grant permissions based on the origin parameter or webContents.getURL() may inadvertently grant permissions to embedded third-party content. The correct requesting URL remains available via details.requestingUrl. Apps that already check details.requestingUrl are not affected. 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 versions prior to 38.8.6, 39.8.1, 40.8.1, and 41.0.0, when an iframe requests permissions (fullscreen, pointerLock, keyboardLock, openExternal, or media), the origin passed to session.setPermissionRequestHandler() incorrectly reflects the top-level page's origin rather than the requesting iframe's origin, potentially allowing embedded third-party content to obtain permissions intended for the parent page.
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
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/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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Check Electron versionRun `npm list electron` in your project directory, or check the electron version in package.json, or run `electron --version` if electron is in PATHAffected if The installed version is less than 38.8.6, or between 39.0.0 and 39.8.1, or between 40.0.0 and 40.8.1, or exactly 41.0.0
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Locate permission handler registrationSearch your codebase for `session.setPermissionRequestHandler` or `session.setPermissionCheckHandler` API callsAffected if A permission handler is registered in your app
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Inspect permission handler implementationExamine the handler function code and look for usage of `details.origin`, `webContents.getURL()`, or any logic that derives the requesting origin from the top-level pageAffected if The handler uses the origin parameter or webContents.getURL() to make permission decisions rather than details.requestingUrl
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Identify iframe usage in the appSearch your codebase or web content for iframe elements, especially those loading third-party or external URLsAffected if Your app embeds iframes, particularly ones that load untrusted third-party content
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Check which permissions are requestedReview your permission handler to see if it handles fullscreen, pointerLock, keyboardLock, openExternal, or media permissionsAffected if The handler processes any of these permission types (fullscreen, pointerLock, keyboardLock, openExternal, media) and uses top-level origin for decisions
You are affected if you run a vulnerable Electron version AND your permission handler relies on the origin parameter or webContents.getURL() to make decisions about iframe-embedded content requesting fullscreen, pointerLock, keyboardLock, openExternal, or media permissions.
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
Upgrade Electron to version 38.8.6, 39.8.1, 40.8.1, or 41.0.0; alternatively, modify permission handlers to check details.requestingUrl instead of relying on the origin parameter.
Electron 38.8.6, 39.8.1, 40.8.1, or latest stable (40.x/41.x branch)
- 1. Identify your current Electron version by checking your package.json or running 'electron --version'
- 2. Determine the appropriate target version based on your current branch: if on 37.x or earlier, target 38.8.6; if on 39.x, target 39.8.1; if on 40.x or 41.x, target 40.8.1 or latest stable
- 3. Update your package.json dependency: 'npm install electron@<target-version> --save-dev' or 'npm install electron@latest'
- 4. Run your application and test that permission requests (fullscreen, pointerLock, keyboardLock, openExternal, media) work correctly
- 5. If your app uses session.setPermissionRequestHandler(), verify that the origin parameter now correctly reflects the iframe's origin rather than the top-level page's origin; also check details.requestingUrl
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-34777 — 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-2026-34777 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