Vulnerability-Lookup

CVE-2026-82021 (GCVE-0-2026-82021)

Vulnerability from cvelistv5 – Published: 2026-08-28 18:50 – Updated: 2026-08-31 18:50 X_Open Source

Title

Hermes Agent 0.18.2 < 0.19.0 MCP Catalog Supply Chain RCE via Mutable Branch Reference

Summary

Hermes Agent 0.18.2 prior to 0.19.0 contains a supply chain vulnerability in its bundled MCP catalog that allows a remote attacker to execute arbitrary code by compromising a third-party upstream repository referenced via a mutable branch rather than a pinned commit SHA. An attacker who compromises the upstream repository can propagate malicious code to every host that installs the affected catalog entry, with no further action required by the operator.

Severity

9 (Critical)


                        
                          CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

8.3 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-31 18:50 UTC

CWE

CWE-494 - Download of Code Without Integrity Check

Assigner

VulnCheck mitre root

References

4 references

URL	Tags
https://github.com/NousResearch/hermes-agent/rele…	release-notes
https://github.com/NousResearch/hermes-agent/pull/64463	issue-trackingpatch
https://github.com/NousResearch/hermes-agent/comm…	patch
https://www.vulncheck.com/advisories/hermes-agent…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version	CPE status
NousResearch	hermes-agent	Affected: 0.18.2 , < 0.19.0 (semver) Affected: 2026.7.7.2 , < 2026.7.20 (custom)	guessed

Date Public

2026-07-14 00:00

Credits

Zubair Ashraf (@zashraf1337), Helmet Security

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-82021

Vulnerability from fkie_nvd - Published: 2026-08-28 20:20 - Updated: 2026-08-31 19:17

Severity

8.3 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H

Summary

References

	URL	Tags
	disclosure@vulncheck.com	https://github.com/NousResearch/hermes-agent/commit/9df5f879b4a5925c0f8f947e7e16ed8e845932c3
	disclosure@vulncheck.com	https://github.com/NousResearch/hermes-agent/pull/64463
	disclosure@vulncheck.com	https://github.com/NousResearch/hermes-agent/releases/tag/v2026.7.20
	disclosure@vulncheck.com	https://www.vulncheck.com/advisories/hermes-agent-mcp-catalog-supply-chain-rce-via-mutable-branch-reference

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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  "published": "2026-08-28T20:20:14.470",
  "references": [
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/NousResearch/hermes-agent/commit/9df5f879b4a5925c0f8f947e7e16ed8e845932c3"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/NousResearch/hermes-agent/pull/64463"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/NousResearch/hermes-agent/releases/tag/v2026.7.20"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://www.vulncheck.com/advisories/hermes-agent-mcp-catalog-supply-chain-rce-via-mutable-branch-reference"
    }
  ],
  "sourceIdentifier": "disclosure@vulncheck.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-494"
        }
      ],
      "source": "disclosure@vulncheck.com",
      "type": "Secondary"
    }
  ]
}

GHSA-W9GW-VGMG-Q67H

Vulnerability from github – Published: 2026-08-28 21:31 – Updated: 2026-08-28 21:31

Details

Severity

8.3 (High)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H

9.0 (Critical)


                  
                    CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Show details on source website

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{
  "affected": [],
  "aliases": [
    "CVE-2026-82021"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-494"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-28T20:20:14Z",
    "severity": "CRITICAL"
  },
  "details": "Hermes Agent 0.18.2 prior to 0.19.0 contains a supply chain vulnerability in its bundled MCP catalog that allows a remote attacker to execute arbitrary code by compromising a third-party upstream repository referenced via a mutable branch rather than a pinned commit SHA. An attacker who compromises the upstream repository can propagate malicious code to every host that installs the affected catalog entry, with no further action required by the operator.",
  "id": "GHSA-w9gw-vgmg-q67h",
  "modified": "2026-08-28T21:31:18Z",
  "published": "2026-08-28T21:31:18Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-82021"
    },
    {
      "type": "WEB",
      "url": "https://github.com/NousResearch/hermes-agent/pull/64463"
    },
    {
      "type": "WEB",
      "url": "https://github.com/NousResearch/hermes-agent/commit/9df5f879b4a5925c0f8f947e7e16ed8e845932c3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/NousResearch/hermes-agent/releases/tag/v2026.7.20"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/hermes-agent-mcp-catalog-supply-chain-rce-via-mutable-branch-reference"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-82021 (GCVE-0-2026-82021)

FKIE_CVE-2026-82021

GHSA-W9GW-VGMG-Q67H

Tags

Sightings

Nomenclature