CVE-2026-70606 in Electron
Summary
by MITRE • 08/05/2026
Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to 40.10.6, 41.9.1, 42.5.1, and 43.0.0, 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. This issue is fixed in versions 40.10.6, 41.9.1, 42.5.1, and 43.0.0.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 08/05/2026
This vulnerability resides within the Electron framework's handling of custom protocol responses, specifically affecting versions prior to 40.10.6, 41.9.1, 42.5.1, and 43.0.0. The flaw manifests when applications employ custom protocol handlers that return ProtocolResponse objects containing a URL but omitting the session parameter. Under normal circumstances, Electron should route these upstream requests through the same session context that originally handled the protocol request. However, due to this implementation error, the framework defaults to using the global defaultSession instead of maintaining session isolation.
The technical implications of this flaw are significant from a security perspective, as it creates a cross-session caching vulnerability that violates fundamental principles of application isolation. When a ProtocolResponse includes a URL but no explicit session reference, Electron's internal logic incorrectly routes the subsequent HTTP request through defaultSession rather than the originating session context. This misrouting allows cached responses to potentially be shared across different session partitions that should remain logically isolated from one another. The vulnerability essentially undermines the security model that applications rely upon when implementing separate sessions for content isolation.
From a threat modeling standpoint, this issue aligns with CWE-284 (Improper Access Control) and CWE-352 (Cross-Site Request Forgery) categories, as it enables unauthorized data leakage between isolated session contexts. The operational impact extends beyond simple information disclosure, potentially enabling more sophisticated attacks where cached responses from one session could be leveraged to influence or manipulate behavior in another session. Attackers could exploit this by crafting protocol responses that reference URLs, causing Electron to serve cached content from a different session context than intended.
The vulnerability creates an attack surface where malicious actors could potentially manipulate session boundaries through carefully crafted custom protocol handlers. Applications that depend on separate sessions for isolating different types of content or user contexts become vulnerable to cross-contamination of cached resources. This issue particularly affects applications implementing complex session management strategies where multiple user sessions or security contexts need to remain completely isolated from one another.
Security practitioners should note this vulnerability's alignment with ATT&CK technique T1059.001 (Command and Scripting Interpreter: PowerShell) through potential exploitation of Electron's JavaScript-based protocol handling mechanisms, though the direct attack vector is more focused on session isolation bypass. The fix implemented in versions 40.10.6, 41.9.1, 42.5.1, and 43.0.0 addresses the core issue by ensuring that ProtocolResponse objects with URLs but no explicit session parameter are properly routed through the session context that originally processed the protocol request rather than defaulting to global session handling. This remediation restores proper session isolation boundaries and prevents the unauthorized sharing of cached responses across isolated application contexts.
Organizations utilizing Electron-based applications should prioritize updating to affected versions, particularly those implementing custom protocol handlers with ProtocolResponse objects containing URL parameters but no explicit session references. The vulnerability represents a subtle but serious degradation of security boundaries that could have far-reaching implications for applications relying on session isolation for proper security implementation. Security controls should include monitoring for potential exploitation attempts through custom protocol handler manipulation and verification that session boundaries remain properly enforced in all application contexts.