CVE-2026-84288: NousResearch hermes-agent ACP Prompt Workflow session.py HermesACPAgent.prompt 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 2026-09-02
Weakness: CWE-404

Description

A vulnerability has been found in NousResearch hermes-agent up to 0.18.2. This affects the function HermesACPAgent.prompt of the file acp_adapter/session.py of the component ACP Prompt Workflow. Such manipulation leads to denial of service. The attack may be performed from remote. The exploit has been disclosed to the public 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, 0.18.1, 0.18.2

References

https://github.com/hackerguopeng/cve/tree/main/Hermes_ACP_Queued_Prompt_DoS_Report
https://vuldb.com/cve/CVE-2026-84288
https://vuldb.com/submit/882873
https://vuldb.com/vuln/397719
https://vuldb.com/vuln/397719/cti

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