CVE-2026-18655

MEDIUMPre-NVD 6.56.5
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 83% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity65% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
17%
KEV
Not listed

Published

August 3, 2026

Last Modified

August 4, 2026

Advisory Details (3)

Auto-updated Aug 3, 2026
Patch available. Sources: github.
github Patch Available

Broker Credential and OAuth Token Disclosure in AWS Labs Amazon MQ MCP Server via Prompt Injection · Advisory · awslabs/mcp · GitHub

https://github.com/awslabs/mcp/security/advisories/GHSA-xwj6-8x5h-hjp6
generic

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

https://aws.amazon.com/security/security-bulletins/2026-070-aws/
generic

awslabs.amazon-mq-mcp-server · PyPI

https://pypi.org/project/awslabs.amazon-mq-mcp-server/2.0.24/

Vendor Advisories for CVE-2026-18655(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 15× in last 7d / 37× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-21 04:28 UTCEG score recompute
  2. 2026-08-20 22:55 UTCEPSS rescore
  3. 2026-08-20 06:27 UTCEG score recompute
  4. 2026-08-19 17:03 UTCEPSS rescore
  5. 2026-08-19 08:26 UTCEG score recompute
  6. 2026-08-18 13:48 UTCEPSS rescore
  7. 2026-08-18 10:25 UTCEG score recompute
  8. 2026-08-17 13:47 UTCEPSS rescore
  9. 2026-08-17 12:23 UTCEG score recompute
  10. 2026-08-16 14:56 UTCEPSS rescore
  11. 2026-08-16 14:19 UTCEG score recompute
  12. 2026-08-16 02:14 UTCEPSS rescore
  13. 2026-08-15 16:18 UTCEG score recompute
  14. 2026-08-15 01:30 UTCEPSS rescore
  15. 2026-08-14 18:16 UTCEG score recompute
  16. 2026-08-13 22:00 UTCEPSS rescore
  17. 2026-08-12 22:14 UTCEG score recompute
  18. 2026-08-12 13:50 UTCEPSS rescore
  19. 2026-08-12 00:13 UTCEG score recompute
  20. 2026-08-11 13:42 UTCEPSS rescore
  21. 2026-08-11 02:13 UTCEG score recompute
  22. 2026-08-11 00:00 UTCEPSS rescore
  23. 2026-08-10 04:12 UTCEG score recompute
  24. 2026-08-09 13:46 UTCEPSS rescore
  25. 2026-08-09 06:12 UTCEG score recompute
Show 12 more
  1. 2026-08-08 16:37 UTCEPSS rescore
  2. 2026-08-08 08:11 UTCEG score recompute
  3. 2026-08-07 10:10 UTCEG score recompute
  4. 2026-08-06 13:46 UTCEPSS rescore
  5. 2026-08-06 12:09 UTCEG score recompute
  6. 2026-08-05 19:17 UTCEPSS rescore
  7. 2026-08-05 14:08 UTCEG score recompute
  8. 2026-08-04 15:10 UTCEPSS rescore
  9. 2026-08-03 20:19 UTCEG score recompute
  10. 2026-08-03 20:13 UTCEG score recompute
  11. 2026-08-03 19:38 UTCEG score recompute
  12. 2026-08-03 19:38 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-18655?
CVE-2026-18655 is a medium vulnerability published on August 3, 2026. 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…
When was CVE-2026-18655 disclosed?
CVE-2026-18655 was first published in the National Vulnerability Database on August 3, 2026, with the most recent update on August 4, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18655 actively exploited?
CVE-2026-18655 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 83.0% of all scored CVEs.
What is the CVSS score of CVE-2026-18655?
CVE-2026-18655 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-18655?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18655, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-18655

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