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

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.

Published: 2026-04-22 Last update: 2026-05-20 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-6855 is rated Low Risk (29.5/100): CVSS High severity, with low exploitation likelihood (EPSS 0.01%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-6855

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-23 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-6855

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.1 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 1.8 5.2 [email protected]

Weakness enumeration for CVE-2026-6855

GitHub Security Advisory for CVE-2026-6855

GHSA-pqmg-c2j8-fq92 · Severity: high · Ecosystem: pip — InstructLab vulnerable to Path Traversal

Affected software / configurations for CVE-2026-6855

Vendor Product Version Raw CPE
redhat instructlab — cpe:2.3:a:redhat:instructlab:-:*:*:*:*:*:*:*
redhat enterprise_linux_ai 3.0 cpe:2.3:o:redhat:enterprise_linux_ai:3.0:*:*:*:*:*:*:*

References for CVE-2026-6855

cvelogic Threat Intelligence