CVE-2026-82021Network attack vector

Arbitrary code execution via mutable catalog reference

Published Aug 28, 2026 · Updated Aug 29, 2026

Supply-chain code execution in Hermes Agent 0.18.2 allows remote attackers to run arbitrary code through an MCP catalog install. The bundled optional-mcps/n8n/manifest.yaml sets install.ref to the mutable main branch, so installation clones code without verifying an immutable commit. Remote attackers must first compromise the referenced third-party repository, and the affected catalog entry must then be installed; the retrieved code executes on the host.

CVSS severity8.3
High
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Supply-chain code execution in Hermes Agent 0.18.2 allows remote attackers to run arbitrary code through an MCP catalog install. The bundled optional-mcps/n8n/manifest.yaml sets install.ref to the mutable main branch, so installation clones code without verifying an immutable commit. Remote attackers must first compromise the referenced third-party repository, and the affected catalog entry must then be installed; the retrieved code executes on the host.

The record

CVE
CVE-2026-82021
Published
Aug 28, 2026
Updated
Aug 29, 2026
Vendor
Nous Research
Product
Hermes Agent
Classifications
CWE-494, T1195.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.18.2 <0.19.0
  2. Affected versionversion=2026.7.7.2 <2026.7.20

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Nous Research · Hermes Agentversion=0.18.2 <0.19.0; version=2026.7.7.2 <2026.7.20

Published CVSS scores

8.3VulnCheckCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
9.0VulnCheckCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-494Download of Code Without Integrity Check
T1195.002Compromise Software Supply Chain

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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