CVE-2020-4077
Context Isolation Bypass vulnerability in electron (npm)
What is CVE-2020-4077 About?
This vulnerability is a context isolation bypass affecting Electron apps using both `contextIsolation` and `contextBridge`. It allows code running in the main world context to reach into the isolated Electron context, enabling privileged actions. The ease of exploitation depends on attackers being able to execute code within the renderer's main world context.
Affected Software
- electron
- <7.2.4
- >8.0.0, <8.2.4
Technical Details
The vulnerability exists in Electron applications that simultaneously use both contextIsolation and contextBridge features. contextIsolation is designed to prevent renderer process code (the 'main world') from accessing Electron's internal APIs or preloaded scripts, thereby enhancing security. contextBridge is intended to safely expose specific, sanitized APIs from the isolated context to the main world. However, due to an oversight or flaw in its implementation, an attacker-controlled script executing within the main world context of the renderer process can escape its isolation. This 'bypass' allows the main world code to directly access or manipulate objects and functions within the Electron-specific isolated context. This grants the attacker the ability to perform privileged actions, such as direct access to Node.js APIs or other sensitive Electron functionalities that should only be available in the isolated context.
What is the Impact of CVE-2020-4077?
Successful exploitation may allow attackers to bypass security boundaries, perform privileged actions, access underlying operating system resources, or achieve arbitrary code execution via compromised Electron APIs.
What is the Exploitability of CVE-2020-4077?
Exploitation requires the ability to execute code in the main world context of the renderer process. This typically means an attacker has already achieved some form of cross-site scripting (XSS) or similar client-side code injection. There are no authentication requirements specific to the bypass itself, but achieving the initial code execution might require it. This is a local privilege escalation if code execution is already present in the renderer, but can be part of a remote attack chain if XSS is achieved remotely. The prerequisites are an Electron app using the specified configurations and a means to inject or execute code in the renderer's main world. The risk is high once renderer code execution is achieved, as it can escalate to full system control.
What are the Known Public Exploits?
| PoC Author | Link | Commentary |
|---|---|---|
| No known exploits | ||
What are the Available Fixes for CVE-2020-4077?
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://github.com/electron/electron/security/advisories/GHSA-h9jc-284h-533g
- https://www.electronjs.org/releases/stable?page=3#release-notes-for-v824
- https://github.com/electron/electron/commit/b8e347709245d2dc5640fbb3044d9b21b4eaa6b0
- https://osv.dev/vulnerability/GHSA-h9jc-284h-533g
- https://www.electronjs.org/releases/stable?page=3#release-notes-for-v824
- https://nvd.nist.gov/vuln/detail/CVE-2020-4077
- https://github.com/electron/electron/security/advisories/GHSA-h9jc-284h-533g
What are Similar Vulnerabilities to CVE-2020-4077?
Similar Vulnerabilities: CVE-2021-26490 , CVE-2022-23507 , CVE-2022-23508 , CVE-2022-23509 , CVE-2023-28929
