Bug 2460013 (CVE-2026-6855)

Summary: CVE-2026-6855 instructlab: InstructLab: Path traversal allows arbitrary directory creation and file write
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: bbrownin
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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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.
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Description OSIDB Bzimport 2026-04-21 08:38:36 UTC 
Path traversal via unsanitized logs_dir in chat session handler. logs_dir passed directly to os.makedirs() and file path construction without boundary validation. Enables arbitrary directory creation and file write.

Affected file: src/instructlab/model/chat.py lines 858-863.
Upstream notification: security-reporting bounced.