{"id":"GHSA-3f6p-5ww8-9rcr","title":"MySQL2: Auth Plugin Downgrade to mysql_clear_password Leaks Plaintext Credentials","summary":"MySQL2: Auth Plugin Downgrade to mysql_clear_password Leaks Plaintext Credentials","severity":"high","cwe":["CWE-522"],"vendor":"mysql2","product":"mysql2","ecosystem":"npm","affected":["mysql2 < 3.22.0"],"patched":["mysql2 3.22.0"],"published":"2026-09-01","updated":"2026-09-01","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-3f6p-5ww8-9rcr","references":[{"url":"https://github.com/sidorares/node-mysql2/security/advisories/GHSA-3f6p-5ww8-9rcr"},{"url":"https://github.com/sidorares/node-mysql2/issues/1617"},{"url":"https://github.com/sidorares/node-mysql2/pull/4236"},{"url":"https://github.com/sidorares/node-mysql2/commit/884bec56288d827939d0dd3f1f4ae476fbc8dbeb"},{"url":"https://github.com/sidorares/node-mysql2/releases/tag/v3.22.0"},{"url":"https://github.com/advisories/GHSA-3f6p-5ww8-9rcr"}],"tags":["ghsa","npm"],"ingestedAt":"2026-09-01T17:29:54.697Z","slug":"GHSA-3f6p-5ww8-9rcr","body":"## Overview\n\n## Summary\n\nA 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.\n\n## Details\n\n`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')`.\n\nNote: `caching_sha2_password` plugin DOES check for SSL before sending cleartext (line 77). But `mysql_clear_password` has no such guard.\n\n## Attack Scenario\n\n1. Attacker operates rogue MySQL server or performs MITM\n2. Server advertises `caching_sha2_password` in handshake\n3. Client sends hashed auth response\n4. Server replies with AuthSwitchRequest to `mysql_clear_password`\n5. Client sends password in plaintext\n6. Attacker captures plaintext password\n\n## PoC\n\nRogue MySQL server (Node.js, ~80 lines) that captures plaintext passwords from mysql2 clients. Tested against mysql2 3.20.0. Full PoC available on request.\n\n## Suggested Fix\n\nRemove `mysql_clear_password` from `standardAuthPlugins`, or add a guard requiring TLS/unix socket before allowing cleartext auth.\n\n## Impact\n\n- mysql2: 9M weekly downloads\n- Any application connecting without TLS is vulnerable to credential theft\n- Cloud environments with untrusted network paths are especially at risk\n\n## Affected packages\n\n- `mysql2 < 3.22.0`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `mysql2 3.22.0`","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}