CVE-2025-57349: openjsf messageformat Prototype Pollution

Vulnerability summary

CVE-2025-57349 is a high (CVSS 7.5) Prototype Pollution vulnerability in openjsf messageformat. EPSS estimates a 0.40% chance of exploitation in the next 30 days, higher than 33% of scored vulnerabilities.

Timeline

1. 24-09-2025
   PublishedVulnerability first disclosed.
2. 29-09-2025
   Last modifiedVulnerability information updated.

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.

• CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.