---
id: CVE-2026-53869
title: >-
  Hermes Agent before 0.16.0 contains a DNS rebinding vulnerability in WebSocket
  endpoints that allows remote attackers to bypass Host and Origin validation
summary: >-
  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/p…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-306
vendor: NousResearch
product: hermes-agent
affected:
  - hermes-agent < 0.16.0
patched:
  - hermes-agent 0.16.0
published: '2026-06-17'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T16:17:20.460'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53869'
references:
  - url: >-
      https://github.com/NousResearch/hermes-agent/commit/d9ec90585cf7616b5972e44cf8d92bb569fc3feb
    label: disclosure@vulncheck.com
  - url: 'https://github.com/NousResearch/hermes-agent/pull/30221'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/NousResearch/hermes-agent/pull/31685'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/NousResearch/hermes-agent/releases/tag/v2026.6.5'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/hermes-agent-dns-rebinding-bypass-via-websocket-endpoints
    label: disclosure@vulncheck.com
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53869'
  - url: 'https://github.com/advisories/GHSA-4pqm-j46f-795x'
tags:
  - nvd
  - cve.org
  - ghsa
  - pip
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-06-18T15:28:51.075482Z'
epss: 0.00592
epssPercentile: 0.48095
ecosystem: pip
ingestedAt: '2026-06-29T14:31:47.160Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-53869)

Affected packages:

- `hermes-agent < 0.16.0`

Patched in:

- `hermes-agent 0.16.0`

Source: https://github.com/advisories/GHSA-4pqm-j46f-795x