CVE-2026-82021 (GCVE-0-2026-82021)
Vulnerability from cvelistv5
Published
2026-08-28 18:50
Modified
2026-08-29 11:48
Severity ?
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
8.3 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
8.3 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
VLAI Severity ?
EPSS score ?
CWE
- CWE-494 - Download of Code Without Integrity Check
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.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| NousResearch | hermes-agent |
Version: 0.18.2 ≤ Version: 2026.7.7.2 < 2026.7.20 |
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "affected",
"packageURL": "pkg:github/NousResearch/hermes-agent",
"product": "hermes-agent",
"repo": "https://github.com/NousResearch/hermes-agent",
"vendor": "NousResearch",
"versions": [
{
"lessThan": "0.19.0",
"status": "affected",
"version": "0.18.2",
"versionType": "semver"
},
{
"lessThan": "2026.7.20",
"status": "affected",
"version": "2026.7.7.2",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "Zubair Ashraf (@zashraf1337), Helmet Security"
}
],
"datePublic": "2026-07-14T00:00:00.000Z",
"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"metrics": [
{
"cvssV4_0": {
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"attackComplexity": "HIGH",
"attackRequirements": "NONE",
"attackVector": "NETWORK",
"baseScore": 9,
"baseSeverity": "CRITICAL",
"exploitMaturity": "NOT_DEFINED",
"privilegesRequired": "NONE",
"providerUrgency": "NOT_DEFINED",
"subAvailabilityImpact": "HIGH",
"subConfidentialityImpact": "HIGH",
"subIntegrityImpact": "HIGH",
"userInteraction": "PASSIVE",
"valueDensity": "NOT_DEFINED",
"vectorString": "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",
"version": "4.0",
"vulnAvailabilityImpact": "HIGH",
"vulnConfidentialityImpact": "HIGH",
"vulnIntegrityImpact": "HIGH",
"vulnerabilityResponseEffort": "NOT_DEFINED"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
},
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 8.3,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "CHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-494",
"description": "Download of Code Without Integrity Check",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-29T11:48:19.100Z",
"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"shortName": "VulnCheck"
},
"references": [
{
"name": "Hermes Agent v2026.7.20 Release Notes",
"tags": [
"release-notes"
],
"url": "https://github.com/NousResearch/hermes-agent/releases/tag/v2026.7.20"
},
{
"name": "Pull Request",
"tags": [
"issue-tracking",
"patch"
],
"url": "https://github.com/NousResearch/hermes-agent/pull/64463"
},
{
"name": "Patch Commit",
"tags": [
"patch"
],
"url": "https://github.com/NousResearch/hermes-agent/commit/9df5f879b4a5925c0f8f947e7e16ed8e845932c3"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.vulncheck.com/advisories/hermes-agent-mcp-catalog-supply-chain-rce-via-mutable-branch-reference"
}
],
"source": {
"discovery": "UNKNOWN"
},
"tags": [
"x_open-source"
],
"title": "Hermes Agent 0.18.2 \u003c 0.19.0 MCP Catalog Supply Chain RCE via Mutable Branch Reference",
"x_generator": {
"engine": "vulncheck"
}
}
},
"cveMetadata": {
"assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"assignerShortName": "VulnCheck",
"cveId": "CVE-2026-82021",
"datePublished": "2026-08-28T18:50:38.180Z",
"dateReserved": "2026-08-27T21:39:20.459Z",
"dateUpdated": "2026-08-29T11:48:19.100Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…