CVE-2026-84289
NousResearch hermes-agent MCP Tool mcp_tool.py list_tools memory allocation
- State
- Published
- Severity
- 5.3 Medium
- Published
- Sep 1, 2026
- Updated
- Sep 2, 2026
- Reserved
- Sep 1, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 5.3 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P | VulDB |
| 3.1 | 4.3 Medium | 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 | VulDB |
| 3.0 | 4.3 Medium | CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R | VulDB |
| 2.0 | 4.0 Medium | AV:N/AC:L/Au:S/C:N/I:N/A:P/E:POC/RL:ND/RC:UR | VulDB |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
hermes-agentNousResearch |
|
References
- VDB-397720 | NousResearch hermes-agent MCP Tool mcp_tool.py list_tools memory allocationvdb-entrytechnical-description
- VDB-397720 | CTI Indicators (IOB, IOC, IOA)signaturepermissions-required
- CVE-2026-84289 | CVE Analysis and Reportthird-party-advisory
- Submit #882960 | NousResearch hermes-agent 0.18.0 Denial of Servicethird-party-advisory
- https://github.com/lche511/cve/blob/main/Hermes_MCP_Tool_Resource_Amplification_DoS_Report/REPORT.mdexploit
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