{"cve":"CVE-2026-86439","nvd":{"published":"2026-09-07T23:16:53.297","modified":"2026-09-08T19:56:50.950","status":"Deferred","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.","cvss_v4":{"vector":"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","score":8.7},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":8.8},"cwes":["CWE-22"],"references":["https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/storage/doc_store.go#L124-L129","https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/storage/memory_store.go#L203-L211","https://github.com/knowns-dev/knowns/commit/09c5a96fd5817b941dc86669278c1a17db10ed4e","https://github.com/knowns-dev/knowns/releases/tag/v0.30.0","https://github.com/knowns-dev/knowns/security/advisories/GHSA-9gfj-28hw-jchp"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:52:03.409947763+00:00"},"epss":{"cve":"CVE-2026-86439","score":0.01079,"percentile":0.65083,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-9gfj-28hw-jchp","url":"https://osv.dev/vulnerability/GHSA-9gfj-28hw-jchp","summary":"Knowns Unrestricted Path Traversal leading to out-of-bounds arbitrary .md file read, write, and deletion in MCP Docs + Memory Tools","modified":"2026-09-25T19:45:09.714130484Z","packages":[{"ecosystem":"npm","name":"knowns","purl":"pkg:npm/knowns","ranges":["<0.30.0"],"fixed":["0.30.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}