CVE-2020-7638: 
JavaScript vulnerability analysis and mitigation

CVE-2020-7638 is a Prototype Pollution vulnerability affecting the confinit package versions below 0.4.0. The vulnerability was discovered by JHU System Security Lab and was disclosed on April 5, 2020. The affected package, confinit, is an Application configuration helper for Node.js (Snyk).

The vulnerability exists in the setDeepProperty function, which could be tricked into adding or modifying properties of Object.prototype using a proto payload. The function fails to properly validate property paths, allowing attackers to manipulate JavaScript language construct prototypes. The vulnerability has been assigned a CVSS base score of 4.2 (medium severity) (Snyk).

The vulnerability can lead to several types of attacks: Denial of Service (DoS) by triggering JavaScript exceptions, Property Injection allowing attackers to manipulate security-critical properties, and potential Remote Code Execution in cases where the codebase evaluates and executes specific object attributes (Snyk).

The vulnerability has been fixed in version 0.4.0 of the confinit package. Recommended mitigations include: upgrading to version 0.4.0 or higher, freezing the prototype using Object.freeze(Object.prototype), requiring schema validation of JSON input, avoiding unsafe recursive merge functions, and considering using objects without prototypes or using Map instead of Object (Snyk).