CVE-2026-34776
MEDIUMCVE-2026-34776 is a medium-severity (CVSS 5.3) Out-of-bounds Read vulnerability in electron. O3 Security confirms whether CVE-2026-34776 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Electron: Out-of-bounds read in second-instance IPC on macOS and Linux
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
electronnpmDescription
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | electron | all versions | 38.8.6 |
| 📦npm | electron | ≥ 39.0.0-alpha.1&&< 39.8.1 | 39.8.1 |
| 📦npm | electron | ≥ 40.0.0-alpha.1&&< 40.8.1 | 40.8.1 |
| 📦npm | electron | ≥ 41.0.0-alpha.1&&< 41.0.0 | 41.0.0 |
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 38.8.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34776 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-2026-34776 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-2026-34776. 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-2026-34776 in your dependencies?
O3 detects CVE-2026-34776 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.