CVE-2026-34765
MEDIUMCVE-2026-34765 is a medium-severity (CVSS 6) CWE-668 vulnerability in electron. O3 Security confirms whether CVE-2026-34765 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Electron named window.open targets not scoped to the opener's browsing context
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
electronnpmDescription
Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to 39.8.5, 40.8.5, 41.1.0, and 42.0.0-alpha.5, when a renderer calls window.open() with a target name, Electron did not correctly scope the named-window lookup to the opener's browsing context group. A renderer could navigate an existing child window that was opened by a different, unrelated renderer if both used the same target name. If that existing child was created with more permissive webPreferences (via setWindowOpenHandler's overrideBrowserWindowOptions), content loaded by the second renderer inherits those permissions. Apps are only affected if they open multiple top-level windows with differing trust levels and use setWindowOpenHandler to grant child windows elevated webPreferences such as a privileged preload script. Apps that do not elevate child window privileges, or that use a single top-level window, are not affected. Apps that additionally grant nodeIntegration: true or sandbox: false to child windows (contrary to the security recommendations) may be exposed to arbitrary code execution. This vulnerability is fixed in 39.8.5, 40.8.5, 41.1.0, and 42.0.0-alpha.5.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | electron | all versions | 39.8.5 |
| 📦npm | electron | ≥ 40.0.0-alpha.1&&< 40.8.5 | 40.8.5 |
| 📦npm | electron | ≥ 41.0.0-alpha.1&&< 41.1.0 | 41.1.0 |
| 📦npm | electron | ≥ 42.0.0-alpha.1&&< 42.0.0-alpha.5 | 42.0.0-alpha.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for electron. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update electron to 39.8.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34765 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-34765 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-34765. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-34765 in your dependencies?
O3 detects CVE-2026-34765 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.