CVE-2026-34767 — electron
MEDIUMCVE-2026-34767 is a medium-severity (CVSS 5.9) CWE-74 vulnerability in electron. A fix is available for electron — see the affected versions and patch details below.
Electron: HTTP Response Header Injection in custom protocol handlers and webRequest
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-2026-34767.
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-2026-34767 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 377,636 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
Apps that register custom protocol handlers via protocol.handle() / protocol.registerSchemesAsPrivileged() or modify response headers via webRequest.onHeadersReceived may be vulnerable to HTTP response header injection if attacker-controlled input is reflected into a response header name or value.
An attacker who can influence a header value may be able to inject additional response headers, affecting cookies, content security policy, or cross-origin access controls.
Apps that do not reflect external input into response headers are not affected.
Workarounds
Validate or sanitize any untrusted input before including it in a response header name or value.
Fixed Versions
41.0.340.8.339.8.338.8.6
For more information
If there are any questions or comments about this advisory, send an email to [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | electron | all versions | 38.8.6npm install electron@38.8.6 |
| 📦npm | electron | ≥ 39.0.0-alpha.1&&< 39.8.3 | 39.8.3npm install electron@39.8.3 |
| 📦npm | electron | ≥ 40.0.0-alpha.1&&< 40.8.3 | 40.8.3npm install electron@40.8.3 |
| 📦npm | electron | ≥ 41.0.0-alpha.1&&< 41.0.3 | 41.0.3npm install electron@41.0.3 |
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 38.8.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34767 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-2026-34767 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-34767. 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-2026-34767 in your dependencies?
O3 Security finds CVE-2026-34767 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.