Vulnerability · Published Aug 3, 2026 · Assigned by AMZN

CVE-2026-18655Broker Credential and OAuth Token Disclosure in AWS Labs Amazon MQ MCP Server via Prompt Injection

Medium 6.5

In plain English

A medium-severity security flaw in amazon-mq-mcp-server from AWS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities).

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.4%top 63.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Improper restriction of intended endpoints in the RabbitMQ broker connection tools of the Amazon MQ MCP Server (awslabs.amazon-mq-mcp-server) before 2.0.24 may allow a remote unauthenticated actor (via prompt injection) to obtain Amazon MQ for RabbitMQ broker credentials or OAuth access tokens sent to a crafted endpoint controlled through a broker hostname introduced in the MCP client context. To remediate this issue, users should upgrade to version 2.0.24.

Affected products (as reported)

Vendor	Product	Versions
AWS	amazon-mq-mcp-server	0 – through 2.0.23

Weakness: CWE-923 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

References

https://pypi.org/project/awslabs.amazon-mq-mcp-server/2.0.24/ release-notes, patch
https://aws.amazon.com/security/security-bulletins/2026-070-aws/ vendor-advisory
https://github.com/awslabs/mcp/security/advisories/GHSA-xwj6-8x5h-hjp6 release-notes