CVE-2026-9354: medium-severity vulnerability in NousResearch hermes-agent
NousResearch hermes-agent Slack Agent/Mattermost Agent escape output
Published · Updated
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33Vexday Risk Score
No sign of exploitation. It has a public proof of concept.
ssvc Attendcvss 6.9epss 0.3%
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: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
Affected products
NousResearch · hermes-agentpublic PoCs found — 1
cve_referencegist.github.com/YLChen-007/e90fb38ac03284176bae49898a3a46a4unverified⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
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