# GHSA-3f6p-5ww8-9rcr: MySQL2: Auth Plugin Downgrade to mysql_clear_password Leaks Plaintext Credentials

> A rogue MySQL server can force the mysql2 driver to send plaintext credentials by downgrading authentication, allowing attackers to steal passwords.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Sep 2026

## What is GHSA-3f6p-5ww8-9rcr?

GHSA-3f6p-5ww8-9rcr is a vulnerability in mysql2, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

## 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

## Which versions are affected by GHSA-3f6p-5ww8-9rcr?

2 open source packages ship an affected version, including mysql2.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mysql2` | npm | All versions | 3.22.0 |
| `mysql2` | npm | All versions | 3.22.0 |

## How do I fix GHSA-3f6p-5ww8-9rcr?

Upgrade mysql2 to 3.22.0 or later.

## Is GHSA-3f6p-5ww8-9rcr being exploited?

There is no known exploitation of GHSA-3f6p-5ww8-9rcr in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-3f6p-5ww8-9rcr and fix it if it is affected.

What it is: GHSA-3f6p-5ww8-9rcr is a vulnerability in mysql2, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-3f6p-5ww8-9rcr in the wild and no public exploit code.

Affected packages and fixed versions:
- mysql2 (npm): affected all versions; fixed in 3.22.0
- mysql2 (npm): affected all versions; fixed in 3.22.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/GHSA-3f6p-5ww8-9rcr/ (Markdown: https://insights.sbomify.com/GHSA-3f6p-5ww8-9rcr/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-3f6p-5ww8-9rcr

---
From sbomify Insights: https://insights.sbomify.com/GHSA-3f6p-5ww8-9rcr/
Summaries are generated and may contain mistakes; the official description above is the record.