Description
A vulnerability was detected in NousResearch hermes-agent up to 2026.4.16. The affected element is an unknown function of the component Slack Agent/Mattermost Agent. The manipulation of the argument format_message results in escaping of output. The attack can be executed remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
Published: 2026-05-24
Score: 6.9 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Wed, 27 May 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Sun, 24 May 2026 05:00:00 +0000

Type Values Removed Values Added
Description A vulnerability was detected in NousResearch hermes-agent up to 2026.4.16. The affected element is an unknown function of the component Slack Agent/Mattermost Agent. The manipulation of the argument format_message results in escaping of output. The attack can be executed remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
Title NousResearch hermes-agent Slack Agent/Mattermost Agent escape output
First Time appeared Nousresearch
Nousresearch hermes-agent
Weaknesses CWE-116
CWE-74
CPEs cpe:2.3:a:nousresearch:hermes-agent:*:*:*:*:*:*:*:*
Vendors & Products Nousresearch
Nousresearch hermes-agent
References
Metrics cvssV2_0

{'score': 6.4, 'vector': 'AV:N/AC:L/Au:N/C:N/I:P/A:P/E:POC/RL:ND/RC:UR'}

cvssV3_0

{'score': 6.5, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L/E:P/RL:X/RC:R'}

cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L/E:P/RL:X/RC:R'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:P'}


Subscriptions

Nousresearch Hermes-agent
cve-icon MITRE

Status: PUBLISHED

Assigner: VulDB

Published:

Updated: 2026-05-27T17:28:00.312Z

Reserved: 2026-05-23T09:19:41.024Z

Link: CVE-2026-9354

cve-icon Vulnrichment

Updated: 2026-05-27T17:27:55.780Z

cve-icon NVD

Status : Deferred

Published: 2026-05-24T05:16:40.537

Modified: 2026-06-17T11:05:05.140

Link: CVE-2026-9354

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-24T08:00:10Z

Weaknesses