This vulnerability in NousResearch hermes-agent affects versions up to 2026.4.16 and is located in an unknown function within the Slack Agent/Mattermost Agent component. The issue arises from improper escaping of output when processing the format_message argument, allowing remote attackers to execute an attack without privileges or user interaction. The CVSS 4.0 base score is 6.9, indicating medium severity. The vendor has not provided any advisory or remediation, and no patch links are available. Exploit code is publicly accessible, increasing the risk of exploitation.

Successful exploitation could allow a remote attacker to manipulate output escaping in the affected component, potentially leading to unintended behavior or information disclosure. The CVSS vector indicates no privileges or user interaction are required, but the impact on confidentiality and availability is limited. There is no indication of integrity impact or system compromise from the provided data.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since the vendor has not responded and no official fix is available, users should monitor for vendor updates. In the meantime, consider restricting network access to the hermes-agent service and reviewing usage of the Slack Agent/Mattermost Agent component to reduce exposure.