CVE-2026-70606: Medium severity npm/electron vulnerability
Impact When a custom protocol handler returned a ProtocolResponse with a url and no session, Electron made the upstream request through defaultSession instead of the session that handled the protocol. A cached response could then be reused across otherwise isolated session partitions.
Apps that use ProtocolResponse.url, omit ProtocolResponse.session, and rely on separate sessions to isolate content are affected. Apps that set an explicit session, or that do not isolate content across sessions, are not affected.
Workarounds Set ProtocolResponse.session explicitly so the request uses the intended session's cache.
Fixed Versions 43.0.0 42.5.1 41.9.1 40.10.6
For more information If you have any questions or comments about this advisory, email Electron at security@electronjs.org
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/electronto a version that resolves this vulnerability.Fixed in 40.10.6 - Upgrade
Upgrade
npm/electronto a version that resolves this vulnerability.Fixed in 41.9.1 - Upgrade
Upgrade
npm/electronto a version that resolves this vulnerability.Fixed in 42.5.1 - Upgrade
Upgrade
npm/electronto a version that resolves this vulnerability.Fixed in 43.0.0 - Upgrade
Upgrade
Electronto a version that resolves this vulnerability.Fixed in 40.10.6 - Upgrade
Upgrade
Electronto a version that resolves this vulnerability.Fixed in 41.9.1 - Upgrade
Upgrade
Electronto a version that resolves this vulnerability.Fixed in 42.5.1 - Upgrade
Upgrade
Electronto a version that resolves this vulnerability.Fixed in 43.0.0 - Configuration
In your custom protocol handler, set ProtocolResponse.session explicitly (do not omit it) so the request uses the intended session’s cache; apps that rely on separate sessions to isolate content are affected when ProtocolResponse.session is omitted.
Electron custom protocol handler (ProtocolResponse) ProtocolResponse.session = Set explicitly