NousResearch hermes-agent Security Flaws

Path traversal in NousResearch hermes-agent through version 2026.4.16 allows remote unauthenticated attackers to bypass path restrictions and modify or disrupt file operations via the read_file tool. The flaw exists in the _is_blocked_device function within tools/file_tools.py. Public exploit code is available (EPSS data not provided, but exploit confirmed). Vendor was notified but did not respond, suggesting no official patch exists at time of analysis.

Missing authorization in NousResearch hermes-agent versions up to 2026.4.16 allows remote attackers to bypass authentication checks in the Batch Runner component, potentially executing unauthorized commands. The vulnerability affects the check_all_command_guards function in tools/approval.py and can be exploited without authentication. Publicly available exploit code exists, though the vulnerability is not yet confirmed in CISA KEV.

Remote injection vulnerability in NousResearch hermes-agent versions up to 2026.4.23 enables unauthenticated attackers to inject malicious payloads through the Skills Guard component's multi-word prompt handling mechanism. The vulnerability has publicly available exploit code and allows attackers to achieve limited confidentiality, integrity, and availability impacts without user interaction. Despite early vendor notification, no response or patch has been provided.

Improper output escaping in NousResearch Hermes Agent versions up to 2026.4.16 allows remote unauthenticated attackers to manipulate message formatting in Slack and Mattermost integrations, potentially leading to information disclosure and service disruption. The vulnerability is exploitable via crafted format_message arguments with low attack complexity and requires no user interaction. Public exploit code is available via GitHub Gist. The vendor did not respond to early disclosure attempts, and no patch availability is documented.

Information disclosure in NousResearch hermes-agent allows remote unauthenticated attackers to extract sensitive data via crafted requests to the Messaging Gateway Handler's environment configuration function. The vulnerability affects versions up to 2026.4.23 with publicly available exploit code demonstrating the attack. EPSS data not provided, but public POC availability increases immediate risk. Vendor has not responded to disclosure, suggesting no official patch timeline.