How severe is CVE-2026-9366?

CVE-2026-9366 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-9366 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-9366?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-9366 have an EU (EUVD) identifier?

Yes. CVE-2026-9366 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31580.

When was CVE-2026-9366 published?

CVE-2026-9366 was published on 2026-05-24 and last updated on 2026-06-17.

CVE-2026-9366

CVE-2026-9366 is a high-severity vulnerability with a CVSS 3.x base score of 7.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-74.

Key facts

Severity: High (CVSS 3.x base score 7.3)
CVSS v2: 7.5
CVSS v4: 5.5
EPSS exploit prediction: 0% (22nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-31580
Weakness: CWE-74
Published: 2026-05-24
Last modified: 2026-06-17

Description

A vulnerability was found in NousResearch hermes-agent 2026.4.23. The impacted element is the function _scan_context_content of the file agent/prompt_builder.py. The manipulation results in injection. The attack may be performed from remote. The exploit has been made public and could be used. The vendor was contacted early about this disclosure but did not respond in any way.

Frequently asked questions

What is CVE-2026-9366?: A vulnerability was found in NousResearch hermes-agent 2026.4.23. The impacted element is the function _scan_context_content of the file agent/prompt_builder.py. The manipulation results in injection. The attack may be performed from remote. The exploit has been made public and could be used. The vendor was contacted early about this disclosure but did not respond in any way.
How severe is CVE-2026-9366?: CVE-2026-9366 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-9366 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-9366?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-9366 have an EU (EUVD) identifier?: Yes. CVE-2026-9366 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31580.
When was CVE-2026-9366 published?: CVE-2026-9366 was published on 2026-05-24 and last updated on 2026-06-17.

References

Other CWE-74 (Improper Neutralization of Special Elements (Injection)) vulnerabilities

CVE-2026-25586 — Critical (CVSS 10.0): SandboxJS is a JavaScript sandboxing library. Prior to 0.8.29, a sandbox escape is possible by shadowing hasOwnProperty…
CVE-2026-25520 — Critical (CVSS 10.0): SandboxJS is a JavaScript sandboxing library. Prior to 0.8.29, The return values of functions aren't wrapped.…
CVE-2025-20265 — Critical (CVSS 10.0): A vulnerability in the RADIUS subsystem implementation of Cisco Secure Firewall Management Center (FMC) Software could…
CVE-2025-20337 — Critical (CVSS 10.0): A vulnerability in a specific API of Cisco ISE and Cisco ISE-PIC could allow an unauthenticated, remote attacker to…
CVE-2025-20281 — Critical (CVSS 10.0): A vulnerability in a specific API of Cisco ISE and Cisco ISE-PIC could allow an unauthenticated, remote attacker to…
CVE-2024-42472 — Critical (CVSS 10.0): Flatpak is a Linux application sandboxing and distribution framework. Prior to versions 1.14.0 and 1.15.10, a malicious…

Browse all CWE-74 (Improper Neutralization of Special Elements (Injection)) vulnerabilities →