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Electron is a popular framework that allows developers to build cross-platform desktop applications using JavaScript, HTML, and CSS. It combines the Chromium rendering engine and Node.js runtime, enabling web technologies to be used for desktop app development. One of Electron’s powerful features is its permission handling system, which allows applications to control access to sensitive device APIs such as serial ports, cameras, and microphones through handlers like session.setPermissionCheckHandler.
The vulnerability identified as CVE-2026-70599 resides in the permission check mechanism for serial-port and media (camera/microphone) requests originating from an iframe. When an iframe embedded in an Electron application requests access to these devices, the framework invokes the `setPermissionCheckHandler` callback to determine whether to grant or deny the request. This handler receives several parameters, including `requestingOrigin` and details.securityOrigin, which are intended to represent the origin of the requesting frame.
However, due to a flaw in the origin propagation logic, the `requestingOrigin` parameter passed to the handler is incorrectly set to the top-level frame’s origin rather than the actual origin of the iframe making the request. This means that if an application’s permission handler relies solely on the `requestingOrigin` parameter to make authorization decisions—for example, by checking if the origin matches a trusted domain—a cross-origin iframe could be granted permissions that were intended only for the top-level application origin.
The root cause of this issue lies in how Electron’s permission system handles the security context of nested frames. While the `details.securityOrigin` field correctly reflects the requesting frame’s origin, the `requestingOrigin` parameter does not follow the same propagation path for these specific permission types. This discrepancy creates a security boundary violation, effectively allowing a malicious or compromised iframe to bypass origin-based access controls and gain unauthorized access to sensitive hardware resources.
This vulnerability is particularly dangerous because it undermines the fundamental same-origin policy that web developers rely on for security. An attacker who can inject or control an iframe within an Electron application could potentially access the user’s webcam, microphone, or connected serial devices without proper authorization, leading to privacy breaches, data exfiltration, or device manipulation. The issue affects all Electron versions prior to the fixed releases: 39.8.7, 40.9.0, 41.2.0, and 42.0.0-beta.1.
DailyCVE Form
Platform: Electron
Version: <39.8.7, <40.9.0, <41.2.0, <42.0.0-beta.1
Vulnerability : Origin Validation Error (CWE-346)
Severity: Medium (CVSS 5.9)
date: 2026-08-05
Prediction: 2026-08-12
What Undercode Say
Undercode’s analysis reveals the technical nuances of this permission bypass. The core issue is the incorrect propagation of the `requestingOrigin` parameter within Electron’s permission check flow. The following artifacts illustrate the problem and the solution:
Vulnerable Handler Logic (Conceptual):
// ❌ VULNERABLE: Relying solely on 'requestingOrigin'
session.setPermissionCheckHandler((webContents, permission, requestingOrigin, details) => {
if (permission === 'serial' || permission === 'media') {
// 'requestingOrigin' is the TOP-LEVEL origin, not the iframe's origin
return trustedOrigins.includes(requestingOrigin);
}
return false;
});
Secure Handler Logic (Fixed):
// ✅ SECURE: Using 'details.securityOrigin'
session.setPermissionCheckHandler((webContents, permission, requestingOrigin, details) => {
if (permission === 'serial' || permission === 'media') {
// 'details.securityOrigin' correctly reflects the requesting iframe's origin
return trustedOrigins.includes(details.securityOrigin);
}
return false;
});
GitHub Advisory Reference:
The official GitHub Security Advisory for this vulnerability is tracked as GHSA-9pf5-hg6p-4pwp. This advisory provides the official disclosure and patch information.
Exploit
An attacker can exploit this vulnerability by embedding a malicious cross-origin iframe within a vulnerable Electron application. The exploitation steps are as follows:
1. Identify a Target Application: The attacker must find an Electron application that uses `session.setPermissionCheckHandler` with origin-based logic to authorize serial-port or media permissions and that delegates these permissions to iframes.
2. Inject or Control an iframe: The attacker needs to inject a cross-origin iframe into the application’s context. This could be achieved through various means, such as cross-site scripting (XSS), compromised third-party content, or man-in-the-middle attacks.
3. Request Device Access: From within the malicious iframe, the attacker uses the Web Serial API or MediaDevices API to request access to a serial port, camera, or microphone.
4. Bypass Origin Check: When the permission check handler is invoked, the `requestingOrigin` parameter will contain the top-level origin (which is trusted by the application’s handler logic). The handler, believing the request comes from the trusted top-level origin, grants the permission.
5. Gain Unauthorized Access: The iframe successfully obtains access to the requested device, allowing the attacker to read data from serial ports, capture video, or record audio without the user’s informed consent.
Protection
To protect against CVE-2026-70599, the following measures are recommended:
– Upgrade Electron: The most effective protection is to upgrade to a patched version of Electron. The fixed versions are 39.8.7, 40.9.0, 41.2.0, and 42.0.0-beta.1 or later. Organizations should prioritize updating their Electron dependencies to these versions.
– Update Permission Handler Logic: If upgrading is not immediately possible, developers should modify their `setPermissionCheckHandler` logic. Instead of relying on the `requestingOrigin` parameter for serial-port and media permissions, they should use details.securityOrigin, which correctly represents the requesting frame’s origin.
– Restrict iframe Permissions: Applications should avoid delegating sensitive device permissions (serial, camera, microphone) to untrusted iframes. If iframe delegation is necessary, implement strict allowlists for iframe origins and validate them using details.securityOrigin.
– Implement Content Security Policy (CSP): Use CSP directives to limit the sources from which iframes can be embedded and to restrict the use of sensitive APIs within iframes.
Impact
The impact of CVE-2026-70599 is significant for applications that rely on origin-based permission checks for device access. Successful exploitation allows a cross-origin iframe to gain unauthorized access to serial ports, cameras, and microphones. This can lead to:
– Privacy Breaches: Unauthorized access to cameras and microphones can result in the capture of sensitive audio and video, potentially exposing confidential conversations or visual information.
– Data Exfiltration: Attackers can read data from connected serial devices, which may include sensitive industrial, medical, or consumer device data.
– Device Manipulation: Unauthorized serial port access could allow attackers to send commands to connected devices, potentially altering their behavior or causing physical damage.
– Privilege Escalation: The vulnerability effectively bypasses the same-origin policy, enabling a cross-origin context to inherit permissions intended for the top-level application origin, violating the principle of least privilege.
– Supply Chain Risk: Applications that embed third-party iframes are particularly at risk, as a compromised third-party component could leverage this vulnerability to access the user’s hardware.
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Sources:
Reported By: github.com
Extra Source Hub:
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