CVE-2026-9354
NousResearch hermes-agent Slack Agent/Mattermost Agent escape output
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
NousResearch hermes-agent Slack Agent/Mattermost Agent escape output
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.
- Record
CVE-2026-9354- CVSS 4.0
- 6.9 Medium
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 - CVSS 3.1
- 6.5 Medium
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 - CVSS 3.0
- 6.5 Medium
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 - CVSS 2.0
- 6.4
AV:N/AC:L/Au:N/C:N/I:P/A:P/E:POC/RL:ND/RC:UR - Weakness
- CWE-116, CWE-74
- Updated
- 2026-11-02
EUVDEUVD-2026-31566
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.
- Record
EUVD-2026-31566- CVSS 4.0
- 6.9 Medium
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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-7pxq-5rjc-m2wr
A vulnerability was detected in NousResearch hermes-agent up to 2026.4.16. The affected element...
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.
- Record
GHSA-7pxq-5rjc-m2wr- CVSS 4.0
- 5.5 Medium
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 - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L - Weakness
- CWE-74
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-9354- CVSS 4.0
- 5.5 Medium
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 - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L - CVSS 2.0
- 6.4 Medium
AV:N/AC:L/Au:N/C:N/I:P/A:P - Weakness
- CWE-74, CWE-116
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-9354 is a medium vulnerability (CVSS 6.9) in Nousresearch Hermes-agent, published May 24, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.34%, the 27th percentile. No source names a fixed version.