CVE-2020-7702: 
JavaScript vulnerability analysis and mitigation

A prototype pollution vulnerability was discovered in the Templ8 JavaScript Client/Server Template Engine, identified as CVE-2020-7702. The vulnerability was published and disclosed on August 17, 2020, with credit given to Beomjin Lee for the discovery. The vulnerability affects all versions of the Templ8 package, with no fixed version available (Snyk).

The vulnerability exists in the parse function of Templ8, allowing for Prototype Pollution attacks. The issue occurs when the package processes template strings containing malicious prototype modifications. The vulnerability has received a CVSS v3.1 base score of 7.5 (High) from Snyk and 9.8 (Critical) from NVD. The attack vector is network-based, with low attack complexity and requires no privileges or user interaction (Snyk).

When exploited, this vulnerability can lead to several severe consequences: Denial of Service (DoS) through manipulation of Object prototype attributes, potential Remote Code Execution if the codebase evaluates and executes specific object attributes, and Property Injection where attackers can pollute security-critical properties like admin privileges. The vulnerability primarily affects application servers, web servers, and web browsers (Snyk).

The vulnerability is easily exploitable through the parse function. A proof of concept exists demonstrating how an attacker can pollute the prototype using a simple template string '{{proto.polluted=true}}'. The attack can be executed remotely without requiring any special privileges or user interaction (Snyk).

Since there is no fixed version available for Templ8, several mitigation strategies are recommended: freeze the prototype using Object.freeze(Object.prototype), implement JSON input schema validation, avoid unsafe recursive merge functions, use objects without prototypes (Object.create(null)), and consider using Map instead of Object as a best practice (Snyk).