CVE-2026-70599 is a medium-severity (CVSS 5.9) CWE-346 vulnerability in electron. A fix is available for electron — see the affected versions and patch details below.
Electron: Permission Check Handler Receives Main Frame Origin Instead of Requesting Iframe Origin
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-70599.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-70599 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
electronnpmDescription
Impact
For serial-port and media (camera / microphone) permission checks made from an iframe, the requestingOrigin passed to session.setPermissionCheckHandler was the top-level frame's origin rather than the requesting frame's. Origin-based handler logic could therefore grant a cross-origin iframe device access intended only for the top-level origin.
Apps are only affected if they use setPermissionCheckHandler with origin-based logic and embed cross-origin iframes with delegated device permissions. Apps that base the decision on details.securityOrigin, or that do not embed such iframes, are not affected.
Workarounds
Check details.securityOrigin instead of requestingOrigin for these permissions, or do not delegate device permissions to untrusted iframes.
Fixed Versions
42.0.0-beta.141.2.040.9.039.8.7
For more information
If you have any questions or comments about this advisory, email Electron at [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | electron | all versions | 39.8.7npm install electron@39.8.7 |
| 📦npm | electron | ≥ 40.0.0-alpha.1&&< 40.9.0 | 40.9.0npm install electron@40.9.0 |
| 📦npm | electron | ≥ 41.0.0-alpha.1&&< 41.2.0 | 41.2.0npm install electron@41.2.0 |
| 📦npm | electron | ≥ 42.0.0-alpha.1&&< 42.0.0-beta.1 | 42.0.0-beta.1npm install electron@42.0.0-beta.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for electron, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update electron to 39.8.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-70599 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-70599 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-70599. 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-2026-70599 in your dependencies?
O3 Security finds CVE-2026-70599 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.