CVE-2026-86439 Details
Description
knowns versions before 0.30.0 fail to validate filesystem paths in MCP tool arguments, allowing attackers to read, create, overwrite and delete files outside the project directory. Attackers can supply path arguments containing directory traversal sequences to access arbitrary Markdown files accessible to the server process.
A path traversal vulnerability has been identified in Knowns versions prior to 0.30.0, specifically within the MCP 'docs' and 'memory' tools. This vulnerability allows attackers to read, create, overwrite, and delete files outside the designated project directory. The issue arises because the application fails to properly validate filesystem paths in arguments in the 'docs' and 'memory' tools, enabling unauthorized access to arbitrary Markdown files that are accessible to the server process.
Users are advised to upgrade to Knowns version 0.30.0 or later, where this vulnerability has been patched.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Sep 7, 2026CISA-ADP
Assessed Sep 8, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-22 | Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| knowns | <= 0.29.1 (semver) |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 8, 2026 | CVE Modified | CISA-ADP |
| Sep 7, 2026 | New CVE Received | [email protected] |