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CVE-2026-9354

NousResearch hermes-agent Slack Agent/Mattermost Agent escape output

Published: May 24, 2026Updated: May 26, 2026 Sources: CVE List NVDCWE-74
NVD MITRE
6.5CVSSMEDIUM
EPSS Score
0.4%
Top 65.9%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:LA:L
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:LIntegrity
Low
A:LAvailability
Low
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Weaknesses

CWE-74CWE-116

Affected Products

hermes-agentNousResearch
Mixed
AI / ML / ai-agent-tooling
nousresearchcommercialAI / MLaka nousresearch, hermes-agent

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

MITRE ATT&CK

2 techniques
Execution
Initial Access
View detailed technique mapping

References

https://gist.github.com/YLChen-007/e90fb38ac03284176bae49898a3a46a4
gist.github.com
https://vuldb.com/submit/812226
vuldb.com
https://vuldb.com/vuln/365317
vuldb.com
and 1 more references View all →

Timeline

Published
May 24, 2026
Last Updated
May 26, 2026

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