What is CVE-2026-9366?

CVE-2026-9366 is a high-severity vulnerability in Nousresearch Hermes-Agent, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 7.3/10. Published 2026-05-24.

How severe is CVE-2026-9366?

High severity. CVSS v3 base score is 7.3 out of 10.

Vulnerability in Nousresearch Hermes-Agent

CVE-2026-9366

A vulnerability was found in NousResearch hermes-agent 2026.4.23. The impacted element is the function _scan_context_content of the file agent/prompt_builder.py. The manipulation results in injection. The attack may be performed from remote. The exploit has been made public and could be used. The vendor was contacted early about this disclosure but did not respond in any way.

EPSS: 0.003 (22.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.

Affected products

Nousresearch Hermes-agent — versions 2026.4.23

Weakness classification (CWE)

References

cna@vuldb.com (technical-description, vdb-entry)
cna@vuldb.com (signature, permissions-required)
cna@vuldb.com (third-party-advisory)
cna@vuldb.com (exploit)

Frequently asked questions

What is CVE-2026-9366?: CVE-2026-9366 is a high-severity vulnerability in Nousresearch Hermes-Agent, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 7.3/10. Published 2026-05-24.
How severe is CVE-2026-9366?: High severity. CVSS v3 base score is 7.3 out of 10.