Vulnerability · Published Sep 24, 2025 · Assigned by mitre
CVE-2025-57349
High 7.5
In plain English
A high-severity prototype pollution in the messageformat package (npm). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
The messageformat package, an implementation of the Unicode MessageFormat 2 specification for JavaScript, is vulnerable to prototype pollution due to improper handling of message key paths in versions prior to 2.3.0. The flaw arises when processing nested message keys containing special characters (e.g., __proto__ ), which can lead to unintended modification of the JavaScript Object prototype. This vulnerability may allow a remote attacker to inject properties into the global object prototype via specially crafted message input, potentially causing denial of service or other undefined behaviors in applications using the affected component.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | messageformat | 3.0.0-beta.0 | GHSA-xfqm-j7pc-xrfc |
Affected products (as reported)
Weakness: CWE-1321 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H