CVE-2026-86439
knowns before 0.30.0 Path Traversal via MCP doc and memory tools
- State
- Published
- Severity
- 8.7 High
- Published
- Sep 7, 2026
- Updated
- Sep 24, 2026
- Reserved
- Sep 7, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.7 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 8.8 High | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | VulnCheck |
Weaknesses
- CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected Products
| Product | Versions |
|---|---|
knownsknowns-dev |
|
References
- GitHub Security Advisory (GHSA-9gfj-28hw-jchp)vendor-advisory
- DocStore.Get path join without containment (v0.29.1)technical-description
- MemoryStore.GetInLayer path join without containment (v0.29.1)technical-description
- knowns fix commit 09c5a96fd581patch
- knowns v0.30.0 Release Notesrelease-notes
- VulnCheck Advisory: knowns before 0.30.0 Path Traversal via MCP doc and memory toolsthird-party-advisory
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