CVE-2026-84287: NousResearch hermes-agent Session Chat api_server.py denial of service

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-01 · updated 2026-09-04
Weakness: CWE-404

Description

A flaw has been found in NousResearch hermes-agent 0.18.0. Affected by this issue is some unknown functionality of the file gateway/platforms/api_server.py of the component Session Chat Interface. This manipulation causes denial of service. The attack is possible to be carried out remotely. The exploit has been published and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Affected products

NousResearch hermes-agent: 0.18.0

References

https://github.com/hackerguopeng/cve/tree/main/Hermes_API_Server_Session_Chat_DoS_Report
https://vuldb.com/cve/CVE-2026-84287
https://vuldb.com/submit/882712
https://vuldb.com/submit/882795
https://vuldb.com/vuln/397718
https://vuldb.com/vuln/397718/cti

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