Quick answers
- Is CVE-2026-9351 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-9351 being exploited in the wild.
- How severe is CVE-2026-9351?
- Medium severity, with a CVSS score of 6.5, published 24 May 2026.
- Which products and versions are affected?
- NousResearch Hermes Agent <= 2026.4.16.
- Is there a fix for CVE-2026-9351?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-9351 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-9351?
- Check whether you run NousResearch Hermes Agent at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A path traversal vulnerability exists in the `_is_blocked_device` function within `tools/file_tools.py` of NousResearch hermes-agent. The function attempts to block access to dangerous device files (like /dev/zero) using `os.path.expanduser()` for normalization, which fails to resolve standard UNIX path sequences like './' or '../'. An attacker can bypass the blocklist by providing a path such as '/dev/./zero', causing the agent to enter an infinite read loop when the OS resolves the path. This results in a process hang or thread exhaustion, particularly impactful in gateway deployments (e.g., Discord or Telegram bots). As of the advisory date, the vendor has not responded to the disclosure.
Affected products
- NousResearch hermes-agent <= 2026.4.16
Timeline
- 2026-04-24: disclosed: Initial discovery and public Gist disclosure
- 2026-05-24: advisory: CVE published to NVD