blue-string-formatter-utils

GHSA-5mc6-ff2p-32qj

Malicious code in blue-string-formatter-utils (npm)

Details

**Severity:** Critical

**Affected versions:** `= 1.0.0`

## Source: amazon-inspector (aa3c9f5edcc636fc8d38e40a6bb225aed8f6b638be31f2abf8b6e747212c9565)
The package advertises itself as 'Utility helpers for string formatting' but its shipped main file performs a single behavior: an XMLHttpRequest GET to the protocol-relative URL //xss.report/c/k3rne111 whose response body is passed directly to eval(). Any require()/import of this package causes arbitrary attacker-controlled JavaScript from xss.report to execute in the consumer's Node process, with no pinning, no integrity check, and no relationship to the advertised functionality. The mismatch between the package's stated purpose (string utilities) and its actual contents (a remote-code loader) is a cover-story pattern.

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/44c218ef24cf0a946ee5662e20e1cd59a1e6a7b6/osv/malicious/npm/blue-string-formatter-utils/MAL-2026-16273.json))

**References:**
- https://github.com/ossf/malicious-packages/blob/44c218ef24cf0a946ee5662e20e1cd59a1e6a7b6/osv/malicious/npm/blue-string-formatter-utils/MAL-2026-16273.json
- https://www.npmjs.com/package/blue-string-formatter-utils/v/1.0.0
- https://github.com/advisories/GHSA-5mc6-ff2p-32qj

Compromised versions (1)

= 1.0.0

Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.