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Vulnerability · Published Sep 1, 2026 · Assigned by VulDB

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

Medium 4.3

In plain English

A medium-severity uncontrolled resource consumption in hermes-agent from NousResearch. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities).

Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.5%top 59.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

VendorProductVersions
NousResearch hermes-agent 0.18.00.18.10.18.2

Weakness: CWE-789, CWE-400 · Vector: 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

References