What’s Vulnerable › Vulnerabilities

CVE-2026-53869: Hermes Agent < 0.16.0 - DNS Rebinding Bypass via WebSocket Endpoints

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-17 · updated 2026-10-26
• Weakness: CWE-306

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.

Affected products

• NousResearch hermes-agent: before 0.16.0 — fixed in 0.16.0

How to fix

Upgrade to a fixed version: NousResearch hermes-agent 0.16.0. Check the vendor advisory for mitigations.

References

• https://github.com/NousResearch/hermes-agent/commit/d9ec90585cf7616b5972e44cf8d92bb569fc3feb
• https://github.com/NousResearch/hermes-agent/pull/30221
• https://github.com/NousResearch/hermes-agent/pull/31685
• https://github.com/NousResearch/hermes-agent/releases/tag/v2026.6.5
• https://www.vulncheck.com/advisories/hermes-agent-dns-rebinding-bypass-via-websocket-endpoints

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