# CVE-2026-6859: InstructLab arbitrary code execution via hardcoded trust_remote_code

Source: https://junglewise.ai/threats/cve-2026-6859-instructlab-arbitrary-code-execution-via-hardcoded-trust-remote  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-22. Updated: 2026-06-30  
License: CC BY 4.0 with a link back

CVE-2026-6859 · Severity: high · CVSS 8.8 · Published 2026-04-22

InstructLab, a tool used for training and interacting with large language models, contains a security flaw that could allow an attacker to take over a user's system. By tricking a user into downloading or training a malicious model from the HuggingFace Hub, an attacker can execute unauthorized commands on the victim's computer. This could lead to the theft of sensitive data or a complete compromise of the affected machine.

Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi), [Redhat](https://junglewise.ai/threats/vendors/redhat).

## Quick answers

**Is CVE-2026-6859 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-6859 being exploited in the wild.

**How severe is CVE-2026-6859?** High severity, with a CVSS score of 8.8, published 22 April 2026.

**Which products and versions are affected?** instructlab (PyPI) ECOSYSTEM:introduced=0,last_affected=0.26.1.

**Is there a fix for CVE-2026-6859?** 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-2026-6859 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-6859?** Check whether you run instructlab (PyPI), Redhat Enterprise Linux Ai or Redhat Instructlab 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 vulnerability exists in InstructLab's `linux_train.py` script where the `trust_remote_code=True` parameter is hardcoded during HuggingFace `from_pretrained()` calls. This bypasses security protections that normally prevent the execution of arbitrary code embedded within model files. A remote attacker can exploit this by hosting a malicious model on the HuggingFace Hub and convincing a user to interact with it using `ilab` commands (train, download, or generate). Successful exploitation results in arbitrary Python code execution with the privileges of the user running the script, potentially leading to full system compromise.

## Affected products

- Red Hat InstructLab -
- Red Hat Red Hat Enterprise Linux AI (RHEL AI) 3 3.0

## Identifiers

- CVE-2026-6859
- GHSA-rxpq-xgqx-fr7p
- PYSEC-2026-2522

## Timeline

- 2026-04-15: advisory: Initial release date of the VEX document
- 2026-04-22: disclosed: NVD publication date

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/security/cve/CVE-2026-6859](https://access.redhat.com/security/cve/CVE-2026-6859)
- [https://bugzilla.redhat.com/show_bug.cgi?id=2459998](https://bugzilla.redhat.com/show_bug.cgi?id=2459998)
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-6859.json](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-6859.json)

## Related threats

- [Red Hat InstructLab path traversal in chat session handler](https://junglewise.ai/threats/cve-2026-6855-red-hat-instructlab-path-traversal-in-chat-session-handler)