TI-2026-57932 Aliases CVE-2026-84289 GHSA-mqg2-c725-2vx3

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

MEDIUM 57CWE-400Published 2026-09-01 · Updated 2026-09-02

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Attack requirements: None
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · Low
Fix status: No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-400.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00471 40th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by the CNA

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
NousResearch	hermes-agent	0.18.0; 0.18.1; 0.18.2	—	No fix listed	CNA

hermes-agent VendorNousResearch Affected 0.18.0; 0.18.1; 0.18.2 Fixed in — No fix listed CNA

CPE names CNA · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:nousresearch:hermes-agent::::::::	—	—	NousResearch

cpe:2.3:a:nousresearch:hermes-agent:*:*:*:*:*:*:*:* Versions — — ·NousResearch

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2026-84289
2026-10-03 Alias added: GHSA-mqg2-c725-2vx3

References

Exploit 1

https://github.com/lche511/cve/blob/main/Hermes_MCP_Tool_Resource_Amplification_DoS_Report/REPORT.md

TI-2026-50258 Hermes Agent 0.18.2 - 0.21.0 RCE via git core.fsmonitor Config Injection CVSS 4.0HIGH 8.6
TI-2026-12325 NousResearch hermes-agent Live Webhook Endpoint base.py extract_media path traversal CVSS 4.0MEDIUM 6.9
TI-2026-08962 NousResearch hermes-agent Webhook Endpoint feishu.py _handle_webhook_request resource consumption CVSS 4.0MEDIUM 6.9
TI-2026-08959 NousResearch hermes-agent run_agent.py _compress_context injection CVSS 4.0MEDIUM 6.9
TI-2026-08958 NousResearch hermes-agent skills_tool.py skill_view injection CVSS 4.0MEDIUM 6.9
TI-2026-08218 NousResearch hermes-agent Environment Variable code_execution_tool.py execute_code sandbox CVSS 4.0MEDIUM 6.9

See all 44 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences