Executive Summary

CVE-2026-5587 is a vulnerability in the MAC-SQL framework, specifically in the Refiner agent's _execute_sql method. This method executes SQL statements generated by a large language model (LLM) without proper validation or sanitization. An attacker can exploit this by injecting malicious SQL through prompt injection, causing the system to run arbitrary and potentially harmful SQL queries.

A proof-of-concept shows that an attacker can inject a recursive Common Table Expression (CTE) that creates an infinite loop, which leads to excessive CPU and memory consumption, potentially crashing the server.

The core issue is the implicit trust in the LLM output without filtering, allowing execution of resource-intensive or dangerous SQL commands.

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Impact Analysis

This vulnerability can lead to severe impacts including denial of service (DoS) by exhausting server CPU, memory, and I/O resources through execution of resource-intensive SQL queries.

It can cause service disruption or complete server crashes, affecting availability and reliability of the affected system.

Since the system executes unvalidated SQL generated by the LLM, it may also allow execution of other malicious SQL commands, potentially compromising data integrity or confidentiality.

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Detection Guidance

This vulnerability can be detected by monitoring for execution of unusual or resource-intensive SQL queries, especially those involving recursive Common Table Expressions (CTEs) or other complex SQL constructs that cause high CPU and memory usage.

One way to detect exploitation attempts is to look for SQL queries similar to the proof-of-concept recursive query that causes infinite loops, such as:

• WITH RECURSIVE infinite_loop(x) AS ( SELECT 1 UNION ALL SELECT x + 1 FROM infinite_loop ) SELECT x FROM infinite_loop;

You can use system monitoring commands to detect high CPU or memory usage by the process running MAC-SQL. For example, on Linux systems:

• top or htop - to monitor CPU and memory usage in real-time.
• ps aux --sort=-%cpu | head -n 10 - to identify processes consuming the most CPU.

Additionally, if you have access to logs or can enable query logging in MAC-SQL or the underlying SQLite database, review logs for suspicious or complex SQL statements.

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Mitigation Strategies

Immediate mitigation steps include implementing strict SQL parsing and validation to allow only safe SQL statements, such as SELECT queries, while blocking dangerous operations like recursive CTEs and ATTACH DATABASE commands.

Additionally, enforce query complexity limits and reduce the maximum execution time to a shorter threshold (for example, 5 seconds) to prevent resource exhaustion and denial of service.

Avoid directly executing SQL statements generated by the language model without proper sanitization or validation.

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Compliance Impact

The vulnerability allows remote attackers to execute arbitrary and potentially malicious SQL queries without proper validation or sanitization, leading to possible service disruption or server crashes.

Such security weaknesses could impact compliance with standards like GDPR and HIPAA, which require protection of data integrity, availability, and confidentiality.

Specifically, denial of service or unauthorized data manipulation caused by this vulnerability may violate requirements for safeguarding personal or sensitive information under these regulations.

However, the provided information does not explicitly discuss compliance implications or specific regulatory impacts.

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