MySQL MCP Server: Missing Origin/Host Validation in SSE Transport Enables Unauthenticated SQL Execution (DNS Rebinding / Direct Exposure)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

10.0 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS

• CVE-2026-59971: 0.42% estimated exploitation activity in the next 30 days; percentile 36.16 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary In SSE/HTTP transport mode, mysqlmcpserver constructs SseServerTransport without passing securitysettings. As a result, the MCP Python SDK's DNS-rebinding protection (Origin/Host header validation) is disabled; the Starlette application has no CORS or TrustedHost middleware; and the service binds to 0.0.0.0 by default with no authentication on any route. Trigger condition: MCPTRANSPORT=sse. The default stdio mode is not affected. Attack Scenarios Scenario A — Direct exposure: Any network attacker can invoke executesql to run arbitrary SQL without credentials → full data dump, and via MySQL FILE privileges, arbitrary file read/write and RCE. Scenario B — DNS rebinding (local bind): An attacker lures a victim's browser to a malicious page, rebinds their domain to 127.0.0.1, and uses the browser as a proxy to invoke executesql as same-origin. Root Cause In src/mysqlmcpserver/server.py: 1. SseServerTransport is constructed without securitysettings — the SDK defaults…

Published by the source

11 Sep 2026, 20:35 UTC

Last modified by the source

1 Oct 2026, 17:55 UTC

Source last checked

26 Oct 2026, 13:51 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-rqfv-2mw9-78g2

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-rqfv-2mw9-78g2

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-rqfv-2mw9-78g2

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# Patch Next advisory brief: CVE-2026-59971

Advisory: MySQL MCP Server: Missing Origin/Host Validation in SSE Transport Enables Unauthenticated SQL Execution (DNS Rebinding / Direct Exposure)
IDs: CVE-2026-59971, GHSA-rqfv-2mw9-78g2
Record: https://patchnext.com/advisories/cve-2026-59971 (revision 3, source checked 26 Oct 2026, 13:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 10.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: mysql-mcp-server 0.4.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI mysql-mcp-server: affected < 0.4.2; fixed in 0.4.2

## Suggested inspection (read-only)
- `python -m pip show mysql-mcp-server`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on mysql-mcp-server.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-rqfv-2mw9-78g2 (GitHub-reviewed advisory GHSA-rqfv-2mw9-78g2 lists affected ranges: PyPI mysql-mcp-server >=0 <0.4.2)
- Verified: https://osv.dev/vulnerability/GHSA-rqfv-2mw9-78g2 (OSV record GHSA-rqfv-2mw9-78g2 lists affected ranges: PyPI mysql-mcp-server >=0 <0.4.2 (fixed))

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