CVE-2022-21718 is a vulnerability in the Electron framework, which is widely used for building cross-platform desktop applications using web technologies such as JavaScript, HTML, and CSS. The vulnerability pertains to improper exposure of resources, classified under CWE-668 (Exposure of Resource to Wrong Sphere). Specifically, in Electron versions prior to 13.6.6, and certain beta and alpha releases up to 17.0.0-alpha.5, renderers can gain unauthorized access to Bluetooth devices through the Web Bluetooth API if the application has not implemented a custom 'select-bluetooth-device' event handler. This event handler is intended to control and restrict which Bluetooth devices can be accessed by the application. Without it, the renderer process—which handles the web content—can access Bluetooth devices directly, potentially exposing sensitive device information or enabling unauthorized interactions with Bluetooth peripherals. The issue arises because the default behavior does not sufficiently isolate or restrict access to Bluetooth devices, leading to exposure of resources to an incorrect security context or sphere. This vulnerability has been addressed in Electron versions 13.6.6, 14.2.4, 15.3.5, 16.0.6, and 17.0.0-alpha.6, where the fix involves enforcing the presence of a custom event handler or otherwise restricting access. Although no known exploits are currently reported in the wild, the vulnerability poses a risk to applications that rely on Electron versions affected by this flaw and that use the Web Bluetooth API without proper event handling. Developers can also apply a workaround by incorporating code from the GitHub Security Advisory to mitigate the issue until they upgrade to a patched Electron version.

For European organizations, the impact of this vulnerability depends on their use of Electron-based applications that leverage the Web Bluetooth API. Potential impacts include unauthorized access to Bluetooth devices connected to user systems, which could lead to leakage of sensitive information from peripherals such as health monitors, security tokens, or industrial control devices. This unauthorized access could also facilitate further attacks, such as device manipulation or man-in-the-middle attacks on Bluetooth communications. The confidentiality and integrity of data transmitted over Bluetooth could be compromised, especially in sectors where Bluetooth-enabled devices are critical, such as healthcare, manufacturing, and smart building management. Availability impact is less direct but could occur if attackers disrupt Bluetooth device functionality. Since Electron is popular among many desktop applications, including internal tools and commercial software, organizations using vulnerable versions without proper mitigations are at risk. The lack of authentication or user interaction requirements for exploitation increases the threat surface, particularly in environments where users run untrusted or third-party Electron apps. However, the medium severity rating and absence of known exploits suggest that while the risk is notable, it is not currently critical. Organizations should nonetheless prioritize remediation to prevent potential exploitation.

1. Upgrade Electron to a patched version: Organizations should update all Electron-based applications to versions 13.6.6, 14.2.4, 15.3.5, 16.0.6, 17.0.0-alpha.6 or later, where the vulnerability is fixed. 2. Implement a custom 'select-bluetooth-device' event handler: Developers must ensure that their Electron applications explicitly define this event handler to control Bluetooth device selection and restrict unauthorized access. 3. Audit Electron applications for Web Bluetooth API usage: Conduct a thorough review of all Electron apps in use to identify those that utilize the Web Bluetooth API and verify proper event handling. 4. Apply GitHub Security Advisory workaround code: Until upgrades can be deployed, apply the recommended code changes from the official advisory to mitigate the vulnerability. 5. Restrict application installation and execution policies: Limit the installation and execution of untrusted or third-party Electron applications, especially those that might access Bluetooth devices. 6. Monitor Bluetooth device access logs: Where possible, enable logging and monitoring of Bluetooth device interactions to detect anomalous or unauthorized access attempts. 7. Educate developers and IT staff: Raise awareness about this specific vulnerability and best practices for secure Bluetooth API usage within Electron apps. These steps go beyond generic advice by focusing on event handler implementation, code-level workarounds, and organizational controls tailored to Electron's architecture and Bluetooth usage.