CVE-2026-84289

MEDIUM 4.3

NousResearch hermes-agent MCP Tool mcp_tool.py list_tools memory allocation

CVSS Score

4.3

EPSS Score

0.0%

EPSS Percentile

0th

A vulnerability was found in NousResearch hermes-agent up to 0.18.2. This vulnerability affects the function list_tools of the file tools/mcp_tool.py of the component MCP Tool. Performing a manipulation results in uncontrolled memory allocation. It is possible to initiate the attack remotely. The exploit has been made public and could be used. The vendor was contacted early about this disclosure but did not respond in any way.

CWE	CWE-789 CWE-400
Vendor	nousresearch
Product	hermes-agent
Published	Sep 1, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R

Attack Vector

Attack Complexity

Privileges Required

User Interaction

Scope

Confidentiality

Integrity

Availability

Affected Versions

NousResearch / hermes-agent

0.18.0 0.18.1 0.18.2

References

NVD ↗ CVE.org ↗ EPSS Data ↗

vuldb.com: https://vuldb.com/vuln/397720 vuldb.com: https://vuldb.com/vuln/397720/cti vuldb.com: https://vuldb.com/cve/CVE-2026-84289 vuldb.com: https://vuldb.com/submit/882960 github.com: https://github.com/lche511/cve/blob/main/Hermes_MCP_Tool_Resource_Amplification_DoS_Report/REPORT.md

Credits

🔍 pengguogood (VulDB User) VulDB CNA Team