CVE-2026-53869

High

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.

SeverityHigh

CVSS7.5

Exploit probability—

ProductHermes-agent

PublishedJun 17, 2026

First seenJun 17, 2026

Weakness typeCWE-306Missing authentication for critical function

How to fix

Update

hermes-agent0.16.0 or later

Patches

github.com/NousResearch/hermes-agent/commit/d9ec90585cf7616b5972e44cf8d92bb569fc3feb

Vendor advisories

github.com/NousResearch/hermes-agent/releases/tag/v2026.6.5

Affected products

Product	Affected versions	Fixed in
hermes-agentPyPI	v < 0.16.0	0.16.0

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