4.3
MEDIUM CVSS 3.1
CVE-2026-84287
NousResearch hermes-agent Session Chat api_server.py denial of service
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.

INFO

Published Date :

Sept. 1, 2026, 9:18 p.m.

Last Modified :

Sept. 4, 2026, 3:17 a.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-84287 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Nousresearch hermes-agent
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 134c704f-9b21-4f2e-91b3-4a467353bcc0
CVSS 2.0 MEDIUM [email protected]
CVSS 3.1 MEDIUM [email protected]
CVSS 4.0 LOW [email protected]
Solution
Apply vendor patches or updates to fix the denial of service vulnerability in the Session Chat Interface.
  • Update NousResearch hermes-agent to the latest version.
  • Apply security patches provided by the vendor.
  • Monitor system for any unusual activity.
  • Review gateway/platforms/api_server.py configurations.
References to Advisories, Solutions, and Tools
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-84287 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-84287 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-84287 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-84287 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Sep. 04, 2026

    Action Type Old Value New Value
    Added SSVC {'id': 'CVE-2026-84287', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-04T02:13:39.532195Z'}
  • New CVE Received by [email protected]

    Sep. 01, 2026

    Action Type Old Value New Value
    Added 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.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
    Added CVSS V2 (AV:N/AC:L/Au:S/C:N/I:N/A:P)
    Added CWE CWE-404
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/84xxx/CVE-2026-84287.json">CVE-2026-84287</a>
    Added Reference https://github.com/hackerguopeng/cve/tree/main/Hermes_API_Server_Session_Chat_DoS_Report
    Added Reference https://vuldb.com/cve/CVE-2026-84287
    Added Reference https://vuldb.com/submit/882712
    Added Reference https://vuldb.com/submit/882795
    Added Reference https://vuldb.com/vuln/397718
    Added Reference https://vuldb.com/vuln/397718/cti
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.