Quick answers
- Is CVE-2026-53869 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-53869 being exploited in the wild.
- How severe is CVE-2026-53869?
- High severity, with a CVSS score of 7.5, published 17 June 2026.
- Which products and versions are affected?
- NousResearch Hermes Agent < 0.16.0; hermes-agent (PyPI) ECOSYSTEM:introduced=0,fixed=0.16.0.
- Is there a fix for CVE-2026-53869?
- Yes. hermes-agent (PyPI): upgrade to 0.16.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-53869 attacked?
- It is attacked over the network, in a network appliance.
- Am I affected by CVE-2026-53869?
- Check whether you run NousResearch Hermes Agent or hermes-agent (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- hermes-agent (PyPI): upgrade to 0.16.0 or later
pip install "hermes-agent>=0.16.0"
Technical details
A DNS rebinding vulnerability exists in the WebSocket endpoints of Hermes Agent's web dashboard. While the application implemented Host-header validation for standard HTTP requests via FastAPI middleware, this middleware does not execute for WebSocket upgrade requests. Consequently, the /api/pty, /api/ws, /api/pub, and /api/events endpoints failed to validate the Host and Origin headers. An attacker can exploit this by inducing a victim's browser to initiate a WebSocket connection to the local agent via a malicious domain. If a valid session token is present (e.g., via the query string), the attacker can bypass the intended loopback/host boundaries to interact with the terminal (PTY) or read event streams. This issue is resolved in version 0.16.0 (v2026.6.5).
Affected products
- NousResearch hermes-agent < 0.16.0
Identifiers
- CVE-2026-53869
- GHSA-4pqm-j46f-795x
- PYSEC-2026-2510
Timeline
- 2026-05-22: other: Initial fix PR submitted
- 2026-05-24: patched: Fix merged into main branch
- 2026-06-05: advisory: Release v0.16.0 published
- 2026-06-17: disclosed: CVE published to NVD
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