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PatchSiren cyber security CVE debrief

CVE-2026-10220 NousResearch CVE debrief

A medium-severity injection vulnerability in NousResearch hermes-agent, affecting versions up to 2026.4.30. The flaw resides in the _serve_plugin_skill/skill_view function within tools/skills_tool.py. Remote attackers can exploit this issue to perform injection attacks. The exploit has been publicly disclosed, and the vendor was contacted but did not respond.

Vendor
NousResearch
Product
hermes-agent
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-01
Original CVE updated
2026-07-22
Advisory published
2026-06-01
Advisory updated
2026-07-22

Who should care

Organizations running NousResearch hermes-agent instances, particularly those exposing skill/plugin functionality to remote or untrusted users. Security teams should prioritize review given public exploit availability and vendor non-response.

Technical summary

The vulnerability exists in the _serve_plugin_skill/skill_view function of tools/skills_tool.py in NousResearch hermes-agent through version 2026.4.30. Insufficient neutralization of special elements allows remote attackers to inject malicious input, leading to injection-based compromise. The attack vector is network-accessible with low attack complexity.

Defensive priority

medium

Recommended defensive actions

  • Review and restrict network access to hermes-agent instances where possible.
  • Inspect tools/skills_tool.py for the _serve_plugin_skill and skill_view functions; apply input validation and output encoding to mitigate injection risks.
  • Monitor for unauthorized or unexpected plugin skill execution in hermes-agent deployments.
  • Apply updates from NousResearch if and when a patched version is released.
  • Review the publicly disclosed technical details to assess exposure and implement targeted mitigations.

Evidence notes

Vuldb-assigned CVE with CVSS 4.0 vector. CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component) and CWE-707 (Improper Neutralization) are cited as weakness types. The vendor field is marked low-confidence and needs review.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-10220 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-10220

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-10220 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-10220

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.