InstructLab Path Traversal Flaw Exposes Local File System
The National Vulnerability Database has identified a critical path traversal vulnerability (CVE-2026-6855) impacting InstructLab. A local attacker can exploit this flaw within the chat session handler by manipulating the logs_dir parameter. This allows for the creation of new directories and the writing of files to arbitrary locations on the affected system, posing a significant risk of unauthorized data modification or disclosure.
With a CVSS score of 7.1 (HIGH), this vulnerability demands immediate attention from defenders. The CWE-22 classification highlights the classic nature of path traversal, a technique attackers frequently leverage to escalate privileges or gain deeper system access. While specific affected products were not detailed by the National Vulnerability Database, any environment running InstructLab should consider this a priority for mitigation.
What This Means For You
- If your organization uses InstructLab, audit your configurations immediately. Focus on how the `logs_dir` parameter is handled and ensure it cannot be influenced by unauthenticated or low-privileged local users. Patching or implementing strict input validation on this parameter is crucial to prevent unauthorized file system access.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
InstructLab Path Traversal - Suspicious Logs Directory Manipulation - CVE-2026-6855
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-6855 | Path Traversal | InstructLab |
| CVE-2026-6855 | Path Traversal | chat session handler |
| CVE-2026-6855 | Path Traversal | manipulating the `logs_dir` parameter |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | April 22, 2026 at 16:16 UTC |
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