| Component | Hermes Agent |
| Severity | high (CVSS 8.3) |
| CVSS vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H |
| Published (NVD) | 2026-08-28 |
| Affected versions | not published yet, see the advisory |
| Fixed in | see the vendor advisory |
| Weakness | CWE-494 |
| CISA KEV | not listed |
NVD description
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.
What to do
- NVD lists no fixed version yet: follow the vendor advisory below and keep Hermes Agent off the public internet until a fix ships.
- Do not expose the component's API or UI to the internet without authentication in front of it.
Sources
- NVD: CVE-2026-82021
- https://github.com/NousResearch/hermes-agent/commit/9df5f879b4a5925c0f8f947e7e16ed8e845932c3
- https://github.com/NousResearch/hermes-agent/pull/64463
- https://github.com/NousResearch/hermes-agent/releases/tag/v2026.7.20
- https://www.vulncheck.com/advisories/hermes-agent-mcp-catalog-supply-chain-rce-via-mutable-branch-reference
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