CVE-2020-4076
Context Isolation Bypass vulnerability in electron (npm)
What is CVE-2020-4076 About?
This is a context isolation bypass vulnerability affecting Electron applications that use `contextIsolation`. An attacker can execute code in the main world renderer context to gain privileged access to the isolated Electron context. This allows an attacker to escalate privileges and perform unauthorized actions, which is a critical and potentially easy exploit if code execution in the renderer is achieved.
Affected Software
- electron
- <7.2.4
- >8.0.0, <8.2.4
Technical Details
The vulnerability represents a context isolation bypass within Electron applications, specifically impacting those that utilize contextIsolation. Context isolation is designed to prevent code running in the main web content (main world) from directly accessing Electron APIs or internal objects available in the isolated context. However, this bypass allows code executing in the main world context within the renderer process to 'reach into' the isolated Electron context. This effectively breaks the security boundary, enabling the attacker's code to access privileged Electron APIs and perform actions that should be restricted, such as filesystem access, inter-process communication, or other sensitive operations. The exact mechanism of the bypass would involve specific techniques to bridge the isolated context or manipulate objects shared across the boundary.
What is the Impact of CVE-2020-4076?
Successful exploitation may allow attackers to bypass security boundaries, escalate privileges, execute arbitrary code with elevated permissions, and gain full control over the Electron application and the underlying operating system.
What is the Exploitability of CVE-2020-4076?
Exploitation complexity is moderate to high, as it requires an initial foothold for code execution within the renderer's main world context. No specific authentication is required at the point of exploit, but prior code execution often implies some form of user interaction (e.g., clicking a malicious link in an Electron-based browser, or injecting code into a trusted application). Privilege requirements start at user-level code execution within the renderer process, which then gets escalated. This is primarily a local vulnerability, requiring the attacker to compromise the Electron application itself. There are no app-side workarounds, meaning the vulnerability is inherent to the Electron framework version. The risk is significantly increased for applications handling untrusted content or allowing arbitrary script execution within the renderer process.
What are the Known Public Exploits?
| PoC Author | Link | Commentary |
|---|---|---|
| No known exploits | ||
What are the Available Fixes for CVE-2020-4076?
Available Upgrade Options
- electron
- <7.2.4 → Upgrade to 7.2.4
- electron
- >8.0.0, <8.2.4 → Upgrade to 8.2.4
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Book a demoAdditional Resources
- https://nvd.nist.gov/vuln/detail/CVE-2020-4076
- https://github.com/electron/electron/security/advisories/GHSA-m93v-9qjc-3g79
- https://www.electronjs.org/releases/stable?page=3#release-notes-for-v824
- https://osv.dev/vulnerability/GHSA-m93v-9qjc-3g79
- https://github.com/electron/electron/security/advisories/GHSA-m93v-9qjc-3g79
- https://www.electronjs.org/releases/stable?page=3#release-notes-for-v824
What are Similar Vulnerabilities to CVE-2020-4076?
Similar Vulnerabilities: CVE-2020-4075 , CVE-2021-22926 , CVE-2021-22927 , CVE-2021-22920 , CVE-2021-22921
