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CVE-2026-84289— NousResearch hermes-agent MCP Tool mcp_tool.py list_tools memory allocation

Quick assessment

Affected
NousResearch hermes-agent
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Nous Research Hermes Agent是Nous Research团队的一个基于机器学习的人工智能代理。 Nous Research Hermes Agent 0.18.2及之前版本存在资源管理错误漏洞，该漏洞源于MCP Tool组件中tools/mcp_tool.py文件的list_tools函数存在不受控制的内存分配，可能导致拒绝服务。

CVSS 4.3 · Medium EPSS 0.47% · P39

Affected Version Matrix 3

VendorProduct Version RangeStatus
NousResearch hermes-agent 0.18.0 affected
0.18.1 affected
0.18.2 affected
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I. Basic Information for CVE-2026-84289

Vulnerability Information
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Vulnerability Title
NousResearch hermes-agent MCP Tool mcp_tool.py list_tools memory allocation
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
未经控制的内存分配
Source: CVE Program / CVE List V5
Vulnerability Title
Nous Research Hermes Agent 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Nous Research Hermes Agent是Nous Research团队的一个基于机器学习的人工智能代理。 Nous Research Hermes Agent 0.18.2及之前版本存在资源管理错误漏洞，该漏洞源于MCP Tool组件中tools/mcp_tool.py文件的list_tools函数存在不受控制的内存分配，可能导致拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
NousResearch hermes-agent 0.18.0 cpe:2.3:a:nousresearch:hermes-agent:*:*:*:*:*:*:*:*

II. Public POCs for CVE-2026-84289

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III. Intelligence Information for CVE-2026-84289

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News Coverage for CVE-2026-84289 (1)

Other References for CVE-2026-84289 (3)

Same Patch Batch · NousResearch · 2026-09-01 · 3 CVEs total

CVE-2026-84287 4.3 MEDIUM NousResearch hermes-agent Session Chat api_server.py denial of service
CVE-2026-84288 4.3 MEDIUM NousResearch hermes-agent ACP Prompt Workflow session.py HermesACPAgent.prompt denial of s

IV. Related Vulnerabilities

Same product: hermes-agent
Same vendor: NousResearch
Same weakness: CWE-789

V. Comments for CVE-2026-84289

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