CVE-2023-45811 – deobfuscator

Package

Manager: npm
Name: deobfuscator
Vulnerable Version: >=2.0.1 <2.4.4

Severity

Level: High

CVSS v3.1: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

EPSS: 0.00126 pctl0.32716

Details

Synchrony deobfuscator prototype pollution vulnerability leading to arbitrary code execution ### Impact A `__proto__` pollution vulnerability exists in synchrony versions before v2.4.4. Successful exploitation could lead to arbitrary code execution. ### Summary A `__proto__` pollution vulnerability exists in the [LiteralMap] transformer allowing crafted input to modify properties in the Object prototype. When executing in Node.js, due to use of the `prettier` module, defining a `parser` property on `__proto__` with a path to a JS module on disk [causes a `require` of the value][prettier/src/main/parser.js] which can lead to arbitrary code execution. ### Patch A fix has been released in `deobfuscator@2.4.4`. ### Mitigation - Upgrade synchrony to v2.4.4 - Launch node with the [--disable-proto=delete][disable-proto] or [--disable-proto=throw][disable-proto] flag ### Proof of Concept Craft a malicious input file named `poc.js` as follows: ```js // Malicious code to be run after this file is imported. Logs the result of shell command "dir" to the console. console.log(require('child_process').execSync('dir').toString()) // Synchrony exploit PoC { var __proto__ = { parser: 'poc.js' } } ``` Then, run `synchrony poc.js` from the same directory as the malicious file. ### Credits This vulnerability was found and disclosed by [William Khem-Marquez][SteakEnthusiast]. [LiteralMap]: src/transformers/literalmap.ts [SteakEnthusiast]: https://github.com/SteakEnthusiast [disable-proto]: https://nodejs.dev/en/api/v20/cli/#--disable-protomode [prettier/src/main/parser.js]: https://github.com/prettier/prettier/blob/2.5.1/src/main/parser.js#L53-L63

Metadata

Created: 2023-10-18T18:27:13Z
Modified: 2025-07-22T15:37:30Z
Source: https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2023/10/GHSA-jg82-xh3w-rhxx/GHSA-jg82-xh3w-rhxx.json
CWE IDs: ["CWE-1321"]
Alternative ID: GHSA-jg82-xh3w-rhxx
Finding: F390
Auto approve: 1