CVE-2026-9351
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA security flaw has been discovered in NousResearch hermes-agent up to 2026.4.16. This vulnerability affects the function _is_blocked_device of the file tools/file_tools.py of the component read_file Tool. Performing a manipulation results in path traversal. The attack may be initiated remotely. The exploit has been released to the public and may be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA path traversal vulnerability exists in the read_file tool's _is_blocked_device function in NousResearch hermes-agent. The function fails to properly validate file paths, allowing attackers to use traversal sequences (e.g., ../../../etc/passwd) to access files outside the intended directory. This can lead to unauthorized read access to sensitive system files.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Confirm hermes-agent installationLocate the hermes-agent package in your environment by checking for the presence of the hermes-agent directory or package, or by running 'pip show hermes-agent' or 'pip list | grep hermes'Affected if hermes-agent is not installed or not found in your environment
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Identify installed versionRun 'pip show hermes-agent' or check your package-lock/requirements file to determine the exact version number installedAffected if the installed version is 2026.4.16 or any version prior to it (e.g., 2026.4.15, 2026.4.1, etc.)
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Verify read_file tool is availableLocate the tools/file_tools.py file within the hermes-agent installation directory and confirm the read_file function exists and is importableAffected if the read_file tool is present and accessible in your deployment
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Inspect _is_blocked_device functionOpen tools/file_tools.py and locate the _is_blocked_device function to examine its path validation logic - check whether it uses proper canonicalization (realpath) and blocks traversal sequencesAffected if the function lacks proper path canonicalization or does not deny access to paths that resolve outside allowed directories
You are affected if hermes-agent is installed with a version at or below 2026.4.16 and the read_file tool with the vulnerable _is_blocked_device function is accessible in your environment.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataImplement robust path canonicalization and validation in the _is_blocked_device function to ensure all file paths resolve within allowed directories. Reject any path containing traversal sequences or absolute paths that escape the sandbox. Additionally, apply the principle of least privilege to file access permissions.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-9351 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-9351 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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