CVE-2026-86439
knowns before 0.30.0 Path Traversal via MCP doc and memory tools
CVSS Score
8.8
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-22 |
| Vendor | knowns-dev |
| Product | knowns |
| Published | Sep 7, 2026 |
| Last Updated | Sep 11, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
knowns-dev / knowns
0 < 0.30.0
References
github.com: https://github.com/knowns-dev/knowns/security/advisories/GHSA-9gfj-28hw-jchp github.com: https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/storage/doc_store.go#L124-L129 github.com: https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/storage/memory_store.go#L203-L211 github.com: https://github.com/knowns-dev/knowns/commit/09c5a96fd5817b941dc86669278c1a17db10ed4e github.com: https://github.com/knowns-dev/knowns/releases/tag/v0.30.0 vulncheck.com: https://www.vulncheck.com/advisories/knowns-before-0.30.0-path-traversal-via-mcp-doc-and-memory-tools
Credits
🔍 Tong Hoang Gia (uziii2208) 🔍 Nguyen Huy Hoang (hoanggxyuuki)