NousResearch hermes-agent Session Chat api_server.py denial of service

published 2026-09-01 2 mo ago modified 2026-09-04 2 mo ago also EUVD-2026-69699

cvss: 4.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits: 0; none known

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.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 2 mo ago (2026-09-04)

Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/hackerguopeng/cve/tree/main/Hermes_API_Server_Session_Chat_DoS_Report referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	5.3	CVSS: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
CNA	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R
CNA	3.0	4.3	CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R
CNA	2.0	4.0	AV:N/AC:L/Au:S/C:N/I:N/A:P/E:POC/RL:ND/RC:UR
CNA	4.0	2.1	CVSS: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/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
CNA	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
CNA	2.0	4.0	AV:N/AC:L/Au:S/C:N/I:N/A:P

Affected products

NousResearch hermes-agent

Classification

Weakness

CWE-404 Improper Resource Shutdown or Release

References

github.com /hackerguopeng/cve/tree/main/Hermes_API_Server_Session_Chat_DoS_Report
exploit
vuldb.com /vuln/397718
vdb-entry
vuldb.com /vuln/397718/cti
signature, permissions-required
vuldb.com /cve/CVE-2026-84287
third-party-advisory
vuldb.com /submit/882712
third-party-advisory
vuldb.com /submit/882795
third-party-advisory

Sources

CVE List CVE-2026-84287
NVD CVE-2026-84287

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary