Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:NSummary
CVE-2026-6855 is a high-severity Path Traversal (CWE-22) vulnerability in Redhat Instructlab. Its CVSS base score is 7.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-6855, published on 2026-04-22, is a path traversal vulnerability (CWE-22) in InstructLab's chat session handler. The flaw allows manipulation of the `logs_dir` parameter, enabling attackers to create new directories and write files to arbitrary locations on the system. This affects InstructLab deployments and has a CVSS v3.1 base score of 7.1 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N), rated as high severity due to its potential for unauthorized data modification or disclosure.
A local attacker with low privileges can exploit this vulnerability with low complexity and no user interaction required. By crafting malicious requests to the chat session handler, the attacker gains the ability to write files outside intended directories, potentially overwriting critical system files, escalating privileges indirectly, or exfiltrating sensitive data through controlled file placements.
Mitigation details are available in the Red Hat security advisory at https://access.redhat.com/security/cve/CVE-2026-6855 and the associated Bugzilla report at https://bugzilla.redhat.com/show_bug.cgi?id=2460013, which likely include patch information and workarounds for affected InstructLab versions.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-24736
Vulnerability Data
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…
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the system, potentially leading to unauthorized data modification or disclosure.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.3.2
Mitigating Controls (NIST 800-53 r5) AI
Enforces the intended directory access authorizations that path traversal would otherwise bypass.
Input validation directly neutralizes special path elements before pathname construction occurs.
Least privilege reduces the impact of any unauthorized file access obtained via traversal.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.
PR.AA-05 defines and reviews access policies but does not address code-level pathname neutralization, so neither direction prevents CWE-22.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development catches path traversal via static/dynamic analysis.
Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.
Application security requirements include rules for safe file handling and canonicalization.
Secure architecture principles require least-privilege file access and directory isolation.
Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.
Information access restriction limits which files an application may read or write.