Medium severity6.5NVD Advisory· Published May 24, 2026· Updated May 26, 2026

CVE-2026-9354

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.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected products

NousResearch/Hermes Agentllm-fuzzy
Range: <=2026.4.16

Patches

Vulnerability mechanics

References

News mentions

NousResearch Hermes Agent: Nine CVEs Disclosed in a Single Day Spanning Injection, Sandbox, and Auth Flaws
Vypr Intelligence · May 24, 2026

Severity

MediumCVSS v3.1

6.5/ 10

CVSS v45.5

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/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

Attack vector: Network
Complexity: Low
Privileges: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: Low

Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

EPSS

Probability of exploitation in the next 30 days.

0.34%

VYPR risk score

Composite of severity, exploitation, and reach.

0.42medium

cvss	0.423
epss	0.000
exploit	0.000
kev	0.000
patch	0.000
ransomware	0.000

Weaknesses

CWE-116
Improper Encoding or Escaping of Output
CWE-74
Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

CVE ID

CVE-2026-9354

Credits

E(
Eric-i (VulDB User)
reporter
VC
VulDB CNA Team
coordinator