CVE-2026-53869 Hermes Agent < 0.16.0 - DNS Rebinding Bypass via WebSocket Endpoints
Remote attackers can bypass Host and Origin validation via DNS rebinding on WebSocket endpoints to inject commands or read terminal output.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-53869?
CVE-2026-53869 is a high-severity vulnerability in NousResearch hermes-agent, published on 17 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-306
Which versions are affected by CVE-2026-53869?
3 open source packages ship an affected version, including hermes-agent.
| Package | Affected | Fixed in |
|---|---|---|
hermes-agent PyPI | All versions | 0.16.0 |
hermes-agent PyPI | All versions | 0.16.0 |
hermes-agent PyPI | All versions | 0.16.0 |
How do I fix CVE-2026-53869?
Upgrade hermes-agent to 0.16.0 or later.
Is CVE-2026-53869 being exploited?
There is no known exploitation of CVE-2026-53869 in the wild and no public exploit code.
Sources
Also known as GHSA-4pqm-j46f-795x, MINI-5mxq-6g44-4f87, MINI-87rj-p2hj-jhgm, MINI-vx7f-692v-4f7c, PYSEC-2026-2510.