CVE-2026-18655 - Broker Credential and OAuth Token Disclosure in AWS Labs Amazon MQ MCP Server via Prompt Injection
criticalvulnerabilityLLM-Specific
security
Source: AWS Security BulletinsAugust 3, 2026
Summary
CVE-2026-18655 is a vulnerability in AWS Amazon MQ MCP Server (a tool that lets AI assistants communicate with Amazon MQ message brokers) versions 2.0.23 and earlier. An attacker can use prompt injection (tricking the AI by hiding instructions in its input) to trick the server into sending broker credentials or OAuth tokens (keys that prove you have permission to access a service) to a fake endpoint they control.
Solution / Mitigation
Update AWS Amazon MQ MCP Server to version 2.0.24 or later.
Classification
Attack Type
Prompt Injection
Attack SophisticationModerate
Impact (CIA+S)
confidentialityintegrity
Affected Vendors
Amazon
Related Issues
Monthly digest — independent AI security research
Original source: https://aws.amazon.com/security/security-bulletins/rss/2026-070-aws/
First tracked: August 3, 2026 at 08:01 PM
Classified by LLM (prompt v3) · confidence: 95%