CVE-2020-7720: Prototype Pollution vulnerability in node-forge (npm)

What is CVE-2020-7720 About?

This vulnerability is a Prototype Pollution flaw in the `node-forge` package via the `util.setPath` function. Attackers can inject arbitrary properties into JavaScript's object prototype chain, potentially leading to application misbehavior, crashes, or even remote code execution in some contexts. While not directly RCE, it can be a stepping stone for more severe attacks, and exploiting it requires manipulating object properties.

Affected Software

node-forge <0.10.0

Technical Details

The node-forge package, specifically versions before 0.10.0, is vulnerable to Prototype Pollution through its util.setPath function. This function, intended for setting nested object properties, does not properly sanitize or validate input. An attacker can craft input strings containing special property names like __proto__ or constructor.prototype which, when processed by util.setPath, allows them to add or modify properties directly on the global JavaScript Object.prototype. This means that newly created objects throughout the application would inherit these injected properties, potentially altering program flow, type confusion, or leading to Denial of Service via unexpected behavior or crashes. In more complex scenarios, it could be chained with other vulnerabilities to achieve Arbitrary Code Execution.

What is the Impact of CVE-2020-7720?

Successful exploitation may allow attackers to inject arbitrary properties into JavaScript object prototypes, which could lead to application crashes, unexpected behavior, and potentially pave the way for other vulnerabilities.

What is the Exploitability of CVE-2020-7720?

Exploitation of this Prototype Pollution vulnerability typically involves a moderate level of complexity. An attacker needs to find an input vector that is processed by the util.setPath function within node-forge and allows for the insertion of __proto__-like property names. Prerequisites include the application using the vulnerable node-forge version and exposing a code path where user-controlled input can modify object properties. Authentication requirements would depend on the accessibility of such an input vector; if it's a public API endpoint, no authentication might be needed. Privilege requirements are low, as the attack targets the application's runtime environment rather than system-level privileges. This is generally a remote exploitation scenario for web applications. The risk is elevated in applications that extensively parse and manipulate nested JSON or object structures from untrusted sources.

What are the Known Public Exploits?

PoC Author	Link	Commentary
No known exploits

What are the Available Fixes for CVE-2020-7720?

A Fix by Resolved Security Exists!

See how we help you strengthen security with automated backported fixes for your libraries.

About the Fix from Resolved Security

This patch removes three utility functions that manipulate object paths (setPath, getPath, deletePath), which could be abused to perform prototype pollution attacks. By deleting these methods, the patch prevents attackers from injecting arbitrary properties into object prototypes, thus fixing CVE-2020-7720 and mitigating the risk of unauthorized code execution or data tampering.

Available Upgrade Options

node-forge
- <0.10.0 → Upgrade to 0.10.0

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Additional Resources

What are Similar Vulnerabilities to CVE-2020-7720?

Similar Vulnerabilities: CVE-2020-7729 , CVE-2021-23369 , CVE-2021-3782 , CVE-2021-3807 , CVE-2022-21696

CVE-2020-7720 Prototype Pollution vulnerability in node-forge (npm)