# diff@4.0.2 security report (npm)

- Verdict: **Needs review** (risk level: medium)
- Scanned: 2026-10-04T16:27:39.000Z
- Files reviewed: 21
- Findings: 2 medium severity findings
- Report: https://security.togoder.click/npm/diff@4.0.2
- Source: Togoder Security (https://security.togoder.click), AI source-code review

## Summary

Togoder Security scanned the npm package diff@4.0.2 on Oct 4, 2026. An AI review of 21 source files produced 2 medium severity findings. The overall verdict is medium: the findings flag risky but common patterns (dynamic code, unsafe defaults, broad file or network access) rather than confirmed malware.

## Findings

### [medium] Dynamic code transformation and registration

Finding ID: `NPS-A1B74D13B997`

File: `runtime.js:1`

The file uses @babel/register at the top level, which hooks into Node's module loading system and dynamically transpiles/executes JavaScript on the fly. While commonly used for development, it enables runtime code transformation and execution outside the package scope, which can be abused to alter or execute arbitrary code during import.

### [medium] Import-time code execution

Finding ID: `NPS-0A24483CACC5`

File: `runtime.js:1`

Requiring runtime.js immediately triggers @babel/register's side effects, modifying global module loading behavior at import time. This is top-level execution and could serve as a vector for code tampering or hidden execution if the dependency or its configuration is compromised.

## Files reviewed

- `runtime.js` (medium): The file registers Babel's runtime transpiler at import time, which modifies module loading behavior and executes code dynamically, posing a moderate security risk if misused or compromised.
- `dist/diff.js` (safe): No malicious patterns detected
- `lib/convert/dmp.js` (safe): No malicious patterns detected
- `lib/convert/xml.js` (safe): The code is a simple XML diff converter that escapes HTML characters and contains no malicious patterns.
- `lib/diff/array.js` (safe): No malicious patterns detected; the file contains a straightforward array diff utility with no network, filesystem, process, or dynamic execution concerns.
- `lib/diff/base.js` (safe): No malicious patterns detected; the code is a standard diff algorithm implementation with no data exfiltration, credential harvesting, obfuscation, or suspicious behavior.
- `lib/diff/character.js` (safe): No malicious patterns detected
- `lib/diff/css.js` (safe): No malicious patterns detected; the code is a standard CSS diff tokenizer with no network, filesystem, or code execution activity.
- `lib/diff/json.js` (safe): No malicious patterns detected
- `lib/diff/line.js` (safe): No malicious patterns detected; the file is a standard diff utility implementation with no network, filesystem, or process access.
- `lib/diff/sentence.js` (safe): No malicious patterns detected; code performs a simple sentence-based diff operation with no network, filesystem, or execution activity.
- `lib/diff/word.js` (safe): No malicious patterns detected
- `lib/index.es6.js` (safe): No malicious patterns detected
- `lib/index.js` (safe): This is a standard index file for the jsdiff library that only exports diff functions and contains no malicious patterns, network calls, file system access, or dynamic code execution.
- `lib/patch/apply.js` (safe): No malicious patterns detected; the code is a standard unified diff patch application utility with no network, filesystem, process execution, or obfuscated payloads.
- `lib/patch/create.js` (safe): No malicious patterns detected; the code is a standard diff/patch generation utility with no network, filesystem, or process execution activity.
- `lib/patch/merge.js` (safe): No malicious patterns detected; the code is a standard patch merging utility with no network, filesystem, process, or dynamic execution risks.
- `lib/patch/parse.js` (safe): No malicious patterns detected; the code is a straightforward unified diff parser with no network, filesystem, process, or dynamic execution activity.
- `lib/util/array.js` (safe): No malicious patterns detected; the file contains only benign array comparison utility functions.
- `lib/util/distance-iterator.js` (safe): No malicious patterns detected
- `lib/util/params.js` (safe): No malicious patterns detected

## Version ranges

None of the 2 scanned versions of diff are flagged high or critical. The latest scanned version, 8.0.4, is clean. Only versions we have scanned are listed; unscanned versions between them are not covered.

- 8.0.4 (`8.0.4`): clean
- 4.0.4 – 8.0.3 (`>=4.0.4 <=8.0.3`): not scanned
- 4.0.2 (`4.0.2`): medium (Dynamic code transformation and registration +1 more)

## Scanned versions

- [8.0.4](https://security.togoder.click/npm/diff@8.0.4): safe, 2026-10-06T14:23:08.000Z
- [4.0.2](https://security.togoder.click/npm/diff@4.0.2): medium, 2026-10-04T16:27:39.000Z

AI analysis is guidance, not a guarantee. Methodology: https://security.togoder.click/methodology