CVE-2026-48774— ProxySQL MCP run_sql_readonly executes side-effecting MySQL multi-statements despite read-only contract

ProxySQL MCP run_sql_readonly executes side-effecting MySQL multi-statements despite read-only contract

ProxySQL is a proxy for MySQL and its forks, as well as PostgreSQL. In versions 3.0.0 through 3.0.8, ProxySQL's GenAI/MCP `run_sql_readonly` tool violates its documented read-only contract for MySQL targets. The tool validates only the full input string with a substring blacklist and first-keyword allowlist, but then executes the entire SQL string on a backend connection created with `CLIENT_MULTI_STATEMENTS`. As a result, a caller can submit a read-only first statement followed by a side-effecting second statement, such as `SELECT 1; RENAME TABLE ...`. The validator accepts the payload because it starts with `SELECT` and because side-effecting MySQL statements such as `RENAME TABLE`, `SET`, `RESET`, `LOCK TABLES`, and `KILL` are not rejected by the blacklist. In a live MCP runtime test, the `/mcp/query` endpoint accepted a `run_sql_readonly` request. The MCP response reported success for the first `SELECT`, and direct backend verification showed that the table had actually been renamed. This violates the endpoint's read-only security contract and lets an MCP caller perform backend writes or administrative SQL, limited by the configured MCP target account's database privileges. Version 3.0.9 contains a fix. Other operator mitigations include: keeping MCP disabled unless required; setting a non-empty `mcp-query_endpoint_auth` token before exposing `/mcp/query`; restricting MCP listener network exposure; configuring MCP backend target credentials as database-level read-only users; and adding temporary MCP query rules to block obvious multi-statement patterns.

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

输入验证不恰当

ProxySQL 输入验证错误漏洞

ProxySQL ProxySQL是ProxySQL组织开源的一个面向MySQL、PostgreSQL及其生态系统的领先数据库代理，支持高性能连接管理、高可用故障转移和实时查询分析。 ProxySQL 3.0.6至3.0.8版本存在输入验证错误漏洞，该漏洞源于输入验证不当，GenAI/MCP `run_sql_readonly`工具只验证完整输入字符串的字典黑名单和首关键字白名单，但随后使用`CLIENT_MULTI_STATEMENTS`创建的后端连接执行整个SQL字符串，允许调用者提交只读第一语句后跟

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