CVE-2026-82021
Hermes Agent 0.18.2 < 0.19.0 MCP Catalog Supply Chain RCE via Mutable Branch Reference
CVSS Score
8.3
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-494 |
| Vendor | nousresearch |
| Product | hermes-agent |
| Published | Aug 28, 2026 |
| Last Updated | Aug 29, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
NousResearch / hermes-agent
0.18.2 < 0.19.0 2026.7.7.2 < 2026.7.20
References
github.com: https://github.com/NousResearch/hermes-agent/releases/tag/v2026.7.20 github.com: https://github.com/NousResearch/hermes-agent/pull/64463 github.com: https://github.com/NousResearch/hermes-agent/commit/9df5f879b4a5925c0f8f947e7e16ed8e845932c3 vulncheck.com: https://www.vulncheck.com/advisories/hermes-agent-mcp-catalog-supply-chain-rce-via-mutable-branch-reference
Credits
Zubair Ashraf (@zashraf1337), Helmet Security