Overview

A significant vulnerability has been identified in the mpregular package, a widely used program development framework based on RegularJS. This vulnerability, tagged as CVE-2025-57323, affects version 0.2.0 and earlier versions. It allows attackers to manipulate properties on Object.prototype, resulting in a potential system compromise or data leakage.

Vulnerability Summary

CVE ID: CVE-2025-57323
Severity: High (7.5 CVSS Score)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Denial of Service, Potential System Compromise, Data Leakage

Affected Products

Product | Affected Versions

mpregular | 0.2.0 and earlier versions

How the Exploit Works

The vulnerability lies in the mp.addEventHandler function of mpregular where it fails to properly validate and sanitize input. An attacker can exploit this by sending a specially crafted payload that can inject properties on Object.prototype. This can cause the application to behave unexpectedly, leading to issues like Denial of Service (DoS) and potentially giving an attacker the ability to compromise the system or leak data.

Conceptual Example Code

Here is a conceptual example of how the vulnerability might be exploited:

var payload = {
"__proto__": {
"isAdmin": true
}
};
mp.addEventHandler(payload);

In this example, a malicious payload is created that injects an “isAdmin” property into the Object prototype. When processed by the mp.addEventHandler function, it could potentially grant admin privileges to an attacker, depending on how the application uses this property.

Mitigation Guidance

The most effective mitigation for this vulnerability is to apply the patch provided by the vendor. If this is not immediately feasible, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) could serve as a temporary mitigation by blocking or alerting on any suspicious activity related to this vulnerability. However, these measures are only stop-gap solutions and cannot replace the need for patching.