NousResearch hermes-agent up to 0.18.2 MCP Tool tools/mcp_tool.py list_tools memory allocation

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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3.9$0-$5k0.51+

Summaryinfo

A vulnerability categorized as problematic has been discovered in NousResearch hermes-agent up to 0.18.2. This issue affects the function list_tools of the file tools/mcp_tool.py of the component MCP Tool. Executing a manipulation can lead to memory allocation. This vulnerability is registered as CVE-2026-84289. It is possible to launch the attack remotely. Furthermore, an exploit is available. The vendor was contacted early about this disclosure but did not respond in any way.

Detailsinfo

A vulnerability classified as problematic 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. The manipulation with an unknown input leads to a memory allocation vulnerability. The CWE definition for the vulnerability is CWE-789. The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated. As an impact it is known to affect availability.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-84289. The exploitation appears to be easy. The attack can be initiated remotely. Technical details and also a public exploit are known.

It is possible to download the exploit at github.com. It is declared as proof-of-concept. The vendor was contacted early about this disclosure but did not respond in any way.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 3.9

VulDB Base Score: 4.3
VulDB Temp Score: 3.9
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Memory allocation
CWE: CWE-789 / CWE-400 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Download: 🔒
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

09/01/2026 Advisory disclosed
09/01/2026 +0 days VulDB entry created
09/01/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Not defined

CVE: CVE-2026-84289 (🔒)
GCVE (CVE): GCVE-0-2026-84289
GCVE (VulDB): GCVE-100-397720
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 09/01/2026 17:54
Changes: 09/01/2026 17:54 (57)
Complete: 🔍
Submitter: pengguogood
Cache ID: 216::103

Submitinfo

Accepted

  • Submit #882960: NousResearch hermes-agent 0.18.0 Denial of Service (by pengguogood)

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