Prototype Pollution Vulnerability in Elysia Framework by ElysiaJS

CVE-2025-66456

What is CVE-2025-66456?

CVE-2025-66456 is a prototype pollution vulnerability found in the Elysia Framework, a TypeScript-based framework designed for request validation, type inference, OpenAPI documentation, and client-server communication. This vulnerability affects versions 1.4.0 through 1.4.16 of the framework and allows malicious actors to exploit the way the framework merges schema validation results. Specifically, the vulnerability arises when merging these results based on the same key, which can inadvertently allow the __proto__ property to be manipulated. This could lead to remote code execution (RCE) if combined with another identified vulnerability, making it a significant threat to organizations that rely on the Elysia Framework for their applications.

Organizations utilizing this framework could face detrimental impacts due to unauthorized access, control, and potential system compromise, which emphasizes the need for immediate remediation.

Potential Impact of CVE-2025-66456

1. Unauthorized Remote Code Execution: The core risk presented by this vulnerability is the potential for remote code execution, allowing attackers to run arbitrary code on affected systems. This could lead to full system compromise and control by the attacker.

2. Data Breach Risks: Exploitation could enable attackers to gain access to sensitive data, leading to significant data breaches. This is particularly concerning for entities handling sensitive customer information, financial data, or proprietary business information.

3. Increased Attack Surface: Due to the nature of this vulnerability, organizations that do not immediately address it may become targets for more complex attacks. If exploited in conjunction with other vulnerabilities or misconfigurations, the overall security posture of the organization could be severely weakened, making them more susceptible to various cyber threats.

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