Hermes Agent contains a DNS rebinding vulnerability in WebSocket endpoints that allows remote attackers to bypass Host and Origin validation
Hermes Agent before 0.16.0 contains a DNS rebinding vulnerability in WebSocket endpoints that allows remote attackers to bypass Host and Origin validation. FastAPI HTTP middleware does not execute for WebSocket upgrade requests on /api/pty, /api/ws, /api/pub, and /api/events endpoints, enabling attackers to exploit DNS rebinding and inject malicious commands or read terminal output.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | hermes-agent | < 0.16.0 | 0.16.0 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-53869
- https://github.com/NousResearch/hermes-agent/pull/30221
- https://github.com/NousResearch/hermes-agent/pull/31685
- https://github.com/NousResearch/hermes-agent/commit/d9ec90585cf7616b5972e44cf8d92bb569fc3feb
- https://github.com/NousResearch/hermes-agent
- https://github.com/NousResearch/hermes-agent/releases/tag/v2026.6.5
- https://www.vulncheck.com/advisories/hermes-agent-dns-rebinding-bypass-via-websocket-endpoints
- https://pypi.org/project/hermes-agent
- https://github.com/advisories/GHSA-4pqm-j46f-795x
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-306- Platform
- Python (PyPI)
- Package
hermes-agent- Disclosed
- 17.06.2026
- Updated
- 11.10.2026 14:18
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-2510 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-4pqm-j46f-795x - CC BY 4.0
Vulnerability history: hermes-agent
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 10
- First → latest
- 05.2026 06.2026
- Without a fix
- 2
- Exploited in attacks
- 0
Severity breakdown
- High 1
- Medium 6
- Low 3
Disclosures per year
- 2026: 10
-
Hermes Agent contains a DNS rebinding vulnerability in WebSocket endpoints that allows remote attackers to bypass Host and Origin validation this entry
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