CVE-2026-59971 MySQL MCP Server: Missing Origin/Host Validation in SSE Transport Enables Unauthenticated SQL Execution (DNS Rebinding / Direct Exposure)
Unauthenticated attackers can execute SQL queries via SSE transport due to missing origin validation and authentication, leading to database disclosure or modification.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-59971?
CVE-2026-59971 is a critical missing authorization vulnerability in designcomputer mysql_mcp_server, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
MySQL MCP Server is a Model Context Protocol server that enables secure interaction with MySQL databases. Prior to 0.4.2, setting MCP_TRANSPORT=sse causes src/mysql_mcp_server/server.py to construct SseServerTransport without security_settings or enable_dns_rebinding_protection, while the Starlette routes /, /sse, and /messages/ have no authentication and the service binds to 0.0.0.0 by default. A network attacker can directly reach execute_sql, or can use DNS rebinding to make a victim's browser relay same-origin requests to a locally bound service, and supply a query that reaches cursor.execute(query). This allows unauthenticated disclosure and modification of the configured database; when the MySQL account has FILE privileges, the same access can read or write server files and may enable code execution. The default stdio transport is not affected. This issue is fixed in 0.4.2.
Which versions are affected by CVE-2026-59971?
3 open source packages ship an affected version, including mysql-mcp-server.
| Package | Affected | Fixed in |
|---|---|---|
mysql-mcp-server PyPI | All versions | 0.4.2 |
mysql-mcp-server PyPI | All versions | 0.4.2 |
mysql-mcp-server PyPI | All versions | 0.4.2 |
How do I fix CVE-2026-59971?
Upgrade mysql-mcp-server to 0.4.2 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-59971 being exploited?
There is no known exploitation of CVE-2026-59971 in the wild and no public exploit code.
Sources
Also known as GHSA-rqfv-2mw9-78g2, PYSEC-2026-4109.