What is CVE-2026-53869?

CVE-2026-53869 is a high-severity vulnerability in Nousresearch Hermes-agent, classified under Missing Authentication for Critical Function. CVSS score: 7.5/10. Published 2026-06-17.

How severe is CVE-2026-53869?

High severity. CVSS v3 base score is 7.5 out of 10.

Auth bypass in Nousresearch Hermes-agent

CVE-2026-53869

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…

Vulnerability class: Broken Authentication

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Nousresearch Hermes-agent — versions 0, 0.16.0

Weakness classification (CWE)

CWE-306 — Missing Authentication for Critical Function

References

disclosure@vulncheck.com (release-notes)
disclosure@vulncheck.com (issue-tracking)
disclosure@vulncheck.com (issue-tracking)
disclosure@vulncheck.com (patch)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2026-53869?: CVE-2026-53869 is a high-severity vulnerability in Nousresearch Hermes-agent, classified under Missing Authentication for Critical Function. CVSS score: 7.5/10. Published 2026-06-17.
How severe is CVE-2026-53869?: High severity. CVSS v3 base score is 7.5 out of 10.