Packages / mysql2 / Security

HighVulnerabilityGHSA-3f6p-5ww8-9rcrPublished 1 Sep 2026

MySQL2: Auth Plugin Downgrade to mysql_clear_password Leaks Plaintext Credentials

Affected releases · mysql2

  • 3.x3.0.0 – 3.21.1Fixed in 3.22.0
  • 2.x and older0.0.1 – 2.3.3No fix, no longer updated

On 3.x, the newest line:

npm install mysql2@3.22.0
3.x

  1. Affected

    3.0.0 – 3.21.1

    84 releases

  2. Fixed

    3.22.0 – 3.24.6

    19 releases, latest

2.x

  1. Affected

    2.0.0 – 2.3.3

    14 releases

1.x

  1. Affected

    1.0.0 – 1.7.0

    27 releases

0.x

  1. Affected

    0.0.1 – 0.15.8

    74 releases

218 stable releases of mysql2, oldest to newest, one row per major.

Is your project affected?

Paste your package.json, or type the range you declare for mysql2. It is read in your browser and sent nowhere.

What happens

Summary

A rogue MySQL server (or MITM) can force mysql2 to send credentials in plaintext by requesting an auth switch to mysql_clear_password. The driver complies without verifying that TLS is active.

Details

mysql_clear_password is registered as a default standard plugin in lib/commands/auth_switch.js (line 21). When a server sends an AuthSwitchRequest (0xFE) requesting mysql_clear_password, the driver executes it without checking for TLS. The plugin (lib/auth_plugins/mysql_clear_password.js) returns Buffer.from(password + '\0').

Note: caching_sha2_password plugin DOES check for SSL before sending cleartext (line 77). But mysql_clear_password has no such guard.

Attack Scenario

  1. Attacker operates rogue MySQL server or performs MITM

  2. Server advertises caching_sha2_password in handshake

  3. Client sends hashed auth response

  4. Server replies with AuthSwitchRequest to mysql_clear_password

  5. Client sends password in plaintext

  6. Attacker captures plaintext password

PoC

Rogue MySQL server (Node.js, ~80 lines) that captures plaintext passwords from mysql2 clients. Tested against mysql2 3.20.0. Full PoC available on request.

Suggested Fix

Remove mysql_clear_password from standardAuthPlugins, or add a guard requiring TLS/unix socket before allowing cleartext auth.

Impact

  • mysql2: 9M weekly downloads

  • Any application connecting without TLS is vulnerable to credential theft

  • Cloud environments with untrusted network paths are especially at risk