Description
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.
CVSS breakdown
CVSS 4.0
Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality (Vulnerable System)
None
Integrity (Vulnerable System)
None
Availability (Vulnerable System)
High
Confidentiality (Subsequent System)
None
Integrity (Subsequent System)
None
Availability (Subsequent System)
None
CVSS 3.1
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected products
- nousresearch / hermes-agent0 – 0.16.0
- nousresearch / hermes-agent0.16.0 – 0.16.0
References
- PATCHhttps://github.com/NousResearch/hermes-agent/releases/tag/v2026.6.5
- PATCHhttps://github.com/NousResearch/hermes-agent/pull/30221
- PATCHhttps://github.com/NousResearch/hermes-agent/pull/31685
- PATCHhttps://github.com/NousResearch/hermes-agent/commit/d9ec90585cf7616b5972e44cf8d92bb569fc3feb
- VENDOR_ADVISORYhttps://www.vulncheck.com/advisories/hermes-agent-dns-rebinding-bypass-via-websocket-endpoints