CVE-2026-84287Public exploitNetwork attack vectorHinoki check available

Authenticated service interruption via concurrency-gate bypass

Published Sep 1, 2026 · Updated Sep 1, 2026

Denial of service in Nous Research Hermes Agent 0.18.0 allows remote authenticated users to interrupt the shared chat service. The session-chat and streaming handlers invoke agent runs without the shared concurrency admission check enforced by other API handlers. Valid API server access permits long-running requests to exceed the configured limit, consume execution and provider capacity, and reject unrelated chat requests.

CVSS severity4.3
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Denial of service in Nous Research Hermes Agent 0.18.0 allows remote authenticated users to interrupt the shared chat service. The session-chat and streaming handlers invoke agent runs without the shared concurrency admission check enforced by other API handlers. Valid API server access permits long-running requests to exceed the configured limit, consume execution and provider capacity, and reject unrelated chat requests.

The record

CVE
CVE-2026-84287
Published
Sep 1, 2026
Updated
Sep 1, 2026
Vendor
Nous Research
Product
Hermes Agent
Classifications
CWE-404, T1499.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.18.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nous Research · Hermes Agentversion=0.18.0

Published CVSS scores

4.0VulDB CNAAV:N/AC:L/Au:S/C:N/I:N/A:P
4.3VulDB CNACVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
2.1VulDB CNACVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-404Improper Resource Shutdown or Release
T1499.003Application Exhaustion Flood

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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