OSV Malicious Advisory
scanned 4h ago · by OpenSSF/OSVOpenSSF/OSV advisory MAL-2026-6921 confirms this npm version as malicious. On require('jsf-utils'), lib/string/pathcase.js runs a top-level async IIFE that fetches a JavaScript payload from https://jsonkeeper.com/b/BPB86 and executes it in-process via Function.constructor with access to the installer's require. The file is auto-loaded because lib/index.js and lib/string/index.js recursively require every module in the tree...
Advisory
MAL-2026-6921
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in jsf-utils (npm)
Details
On require('jsf-utils'), lib/string/pathcase.js runs a top-level async IIFE that fetches a JavaScript payload from https://jsonkeeper.com/b/BPB86 and executes it in-process via Function.constructor with access to the installer's require. The file is auto-loaded because lib/index.js and lib/string/index.js recursively require every module in the tree. The exported pathcase function additionally spawns a detached, stdio-ignored `node` child process using the fetched script as argv, extending execution beyond the import-time IIFE and surviving parent exit. The remote-fetch-and-eval logic is placed inside a file whose stated purpose is a trivial string helper (pathcase), with the original benign implementation left commented out below the payload — concealment inside an innocuous utility. The package impersonates jonschlinkert/utils by reusing that project's author, homepage, and repository metadata while shipping under the name jsf-utils. Because the payload host is a mutable anonymous paste service, the executed code can be changed by the attacker at any time without republishing the package.
## Source: ghsa-malware (17ec4d3467dc2baf85fbb6a18391ee4fd7d59044080f07cde071705f9f28097a) Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
Decision reason
No blocking static signals were detected.
References
Decision evidence
public snapshotBehavioral surface
ChildProcessDynamicRequireFilesystemNetwork
UrlStrings
Source & flagged code
1 flagged · loading sourceindex.jsView file
9L10: module.exports = require('./lib');
Medium
Findings
2 Medium3 Low
MediumDynamic Requireindex.js
MediumNetwork
LowScripts Present
LowFilesystem
LowUrl Strings