CVE-2026-9353: NousResearch hermes-agent Skills Guard Multi-Word Prompt skills_guard.py injection
A security vulnerability has been detected in NousResearch hermes-agent up to 2026.4.23. Impacted is an unknown function of the file agent/skillsguard.py of the component Skills Guard Multi-Word Prompt Handler. The manipulation of the argument THREATPATTERNS 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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Remove
Remove
NousResearch hermes-agent (Skills Guard Multi-Word Prompt Handler)from your environment.If the Skills Guard Multi-Word Prompt Handler is not required, uninstall or remove the handler (agent/skills_guard.py or the corresponding skills module) to eliminate the vulnerable code path.
- Configuration
Ensure THREAT_PATTERNS is not accepted from untrusted sources. Apply strict validation, escaping, or a fixed allow-list for THREAT_PATTERNS values; if validation cannot be guaranteed, disable acceptance of external THREAT_PATTERNS inputs.
NousResearch hermes-agent (agent/skills_guard.py - Skills Guard Multi-Word Prompt Handler) THREAT_PATTERNS input validation = sanitize/validate/deny untrusted input - Compensating control
Restrict network access to the hermes-agent instance (block/limit agent/management ports, allow only trusted IPs, or isolate the host) to prevent remote exploitation until a vendor patch or official fix is available.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-9353?
The severity of CVE-2026-9353 is high with a score of 7.3.
What components of NousResearch hermes-agent are affected by CVE-2026-9353?
CVE-2026-9353 affects the Skills Guard Multi-Word Prompt Handler in the file agent/skills_guard.py.
How do I exploit CVE-2026-9353?
CVE-2026-9353 can be exploited by manipulating the THREAT_PATTERNS argument for injection.
What is the impact of CVE-2026-9353?
The impact of CVE-2026-9353 includes the potential for remote exploitation through injection.
How can I mitigate CVE-2026-9353?
To mitigate CVE-2026-9353, ensure your version of NousResearch hermes-agent is updated beyond 2026.4.23.