Use After Free in Adonisjs with Cockroachdb

A Use After Free (UAF) class of issue can occur in an AdonisJS application interacting with CockroachDB when an object or buffer is deallocated or reused while a database query or client session still holds a reference to it. In the JavaScript/TypeScript runtime this often surfaces as retaining references to query result rows, prepared statement handles, or pooled connections after they are logically released, then inadvertently reading or writing through those stale references.

With CockroachDB, this can be triggered by patterns such as:

• Reusing a row object after releasing a client or query result, for example when manually managing knex or @cockroachdb/cockroach-js client instances and result rows.
• Sharing mutable objects between concurrent query callbacks where one callback releases a reference and another still uses it, leading to race conditions exacerbated by CockroachDB’s distributed SQL behavior and network latency.
• Improper cleanup of transaction callbacks or session pools where a transaction result is accessed after the transaction or client has been released.

Consider a route that prepares a statement, executes it with varying parameters, and then manually nulls or reuses buffers without ensuring all asynchronous work is complete:

const { Client } = require('@cockroachdb/cockroach-js');
const client = new Client({ connectionString: 'postgresql://localhost:26257/mydb' });

async function unsafeQuery(userId) {
  await client.connect();
  const result = await client.query('SELECT id, name FROM users WHERE id = $1', [userId]);
  // Risk: result.rows retained; if client or internal buffer is released/reused here,
  // downstream use of result.rows may become unsafe.
  await client.end(); // client released
  return result.rows; // Use After Free: rows may refer to released memory/state
}

In a distributed setup, CockroachDB’s multi-node execution can extend the window where a reference is held across network hops, increasing the chance that a consumer acts on a row after the client-side representation has been invalidated. If AdonisJS controllers or services cache or share these rows improperly, or if background jobs access stale result sets, the application may read corrupted data or trigger runtime errors.

Another common pattern is binding query results directly to models or request-scoped objects without copying values, then reusing those objects across requests. Because CockroachDB supports long-running distributed transactions and asynchronous commit, a result that appears valid immediately after query completion might be tied to a transaction that later aborts or a connection that gets returned to the pool and reused.

To detect such issues, middleBrick scans unauthenticated attack surfaces and maps findings to frameworks such as OWASP API Top 10 and checks involving unsafe consumption patterns. Its LLM/AI Security module also probes for exposed system prompts and output exfiltration that might accompany a compromised endpoint.

Remediation focuses on ensuring object lifetimes are strictly managed, copies are made where necessary, and concurrency is handled so that no use-after-free window remains. Below are concrete, CockroachDB-specific fixes for AdonisJS.

1) Isolate and copy row data before releasing clients

Do not return raw query rows that may reference client-internal buffers. Instead, serialize the data before closing the client or transaction.

const { Client } = require('@cockroachdb/cockroach-js');

async function safeQuery(userId) {
  const client = new Client({ connectionString: 'postgresql://localhost:26257/mydb' });
  await client.connect();
  try {
    const result = await client.query('SELECT id, name, email FROM users WHERE id = $1', [userId]);
    // Copy values to ensure no stale references
    const rowsCopy = result.rows.map(row => ({ ...row }));
    return rowsCopy;
  } finally {
    await client.end();
  }
}

2) Use transactions properly with async/await and avoid reusing result objects

When using CockroachDB transactions in AdonisJS, keep the transaction scope narrow and ensure all async work completes before releasing the transaction object.

const { Client } = require('@cockroachdb/cockroach-js');

async function updateUserWithinTx(userId, newName) {
  const client = new Client({ connectionString: 'postgresql://localhost:26257/mydb' });
  await client.connect();
  const tx = await client.transaction();
  try {
    const res = await tx.query('UPDATE users SET name = $1 WHERE id = $2 RETURNING id', [newName, userId]);
    const updated = res.rows[0];
    await tx.commit();
    // Use a copy if you must retain beyond the transaction
    return { ...updated };
  } catch (err) {
    await tx.rollback();
    throw err;
  } finally {
    await client.end();
  }
}

3) Validate and sandbox data before model binding

In AdonisJS, prefer explicit DTOs or sanitization instead of binding query rows directly to models to avoid inadvertent reuse of internal fields.

const User = use('App/Models/User');

async function getUserSafe(userId) {
  const client = new Client({ connectionString: 'postgresql://localhost:26257/mydb' });
  await client.connect();
  try {
    const result = await client.query('SELECT id, username FROM users WHERE id = $1', [userId]);
    const row = result.rows[0];
    if (!row) return null;
    // Map to a model or DTO, not direct row reuse
    const user = new User();
    user.merge(row); // explicit copy/merge
    return user;
  } finally {
    await client.end();
  }
}

4) Enforce serial access for shared mutable objects

If you cache query results, ensure mutations and releases are serialized to prevent one async path from freeing memory while another reads it.

const mutex = require('async-mutex').withTimeout;
const cache = new Map();
const cacheMutex = mutex();

async function getOrFetchUser(userId) {
  const release = await cacheMutex();
  try {
    if (cache.has(userId)) {
      // Return a copy to avoid external mutation after release
      return JSON.parse(JSON.stringify(cache.get(userId)));
    }
    const client = new Client({ connectionString: 'postgresql://localhost:26257/mydb' });
    await client.connect();
    const result = await client.query('SELECT id, display_name FROM users WHERE id = $1', [userId]);
    const safeCopy = result.rows.map(r => ({ ...r }));
    cache.set(userId, safeCopy);
    return safeCopy;
  } finally {
    release();
  }
}

These patterns reduce the risk of Use After Free by controlling object lifetimes, copying data out of CockroachDB driver-managed structures, and avoiding shared mutable state across asynchronous boundaries. middleBrick’s scans can highlight insecure consumption and unsafe handling patterns; its GitHub Action can enforce security gates in CI/CD pipelines, and the MCP Server enables scanning APIs directly from development tools.