CVE-2026-9353 Details
Description
A security vulnerability has been detected in NousResearch hermes-agent up to 2026.4.23. Impacted is an unknown function of the file agent/skills_guard.py of the component Skills Guard Multi-Word Prompt Handler. The manipulation of the argument THREAT_PATTERNS leads to injection. Remote exploitation of the attack is possible. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
A critical prompt injection vulnerability has been identified in NousResearch hermes-agent versions through 2026.4.23. The issue resides in the Skills Guard Multi-Word Prompt Handler, specifically within the file agent/skills_guard.py. The vulnerability allows remote exploitation by manipulating the THREAT_PATTERNS argument, leading to injection that bypasses critical detection filters. This could enable the installation of malicious skills that alter the AI agent's core behaviors.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed May 24, 2026CISA-ADP
Assessed May 26, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://gist.github.com/YLChen-007/82a3539d6358842e69dfaef0a9fcf14a | [email protected] | ExploitTechnical Description |
| https://vuldb.com/submit/812216 | [email protected] | Permission Required |
| https://vuldb.com/vuln/365316 | [email protected] | AdvisoryPermission Required |
| https://vuldb.com/vuln/365316/cti | [email protected] | AdvisoryPermission Required |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-707 | Improper Neutralization | [email protected] |
| CWE-74 | Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| NousResearch hermes-agent | <= v2026.4.23 (semver) |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 23, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 24, 2026 | New CVE Received | [email protected] |