CVE-2026-84289CWE-400CWE-789denial-of-service

CVE-2026-84289

Medium · published September 2, 2026

CVSS v3.1
4.3
EPSS
0%
Percentile
39.7
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
4.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
CVSS v4.0
5.3 · 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
EPSS
0.00471 · 39.7th percentile
Weaknesses
CWE-400 · Uncontrolled Resource Consumption; CWE-789 · Memory Allocation with Excessive Size Value
Published
2026-09-02T02:17Z
References (5)
https://github.com/lche511/cve/blob/main/Hermes_MCP_Tool_Resource_Amplification_DoS_Report/REPORT.md · [email protected]https://vuldb.com/cve/CVE-2026-84289 · [email protected]https://vuldb.com/submit/882960 · [email protected]https://vuldb.com/vuln/397720 · [email protected]https://vuldb.com/vuln/397720/cti · [email protected]
EPSS history
Timeline
  • 03 SEP 03:32Z
    EPSS moved — → 0%
    epss
  • 01 SEP 21:45Z
    NousResearch hermes-agent MCP Tool mcp_tool.py list_tools memory allocation
    cvelistv5