CVE-2026-86439
HighCVSS 8.8Summary
Vulnerability in 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.
Risk Assessment
The risk includes unauthorized access to files, modification, or deletion, which could lead to breach of confidentiality, integrity, and availability of data.
Recommendation
Update knowns to version 0.30.0 or later, which includes path validation. Restrict server process privileges and monitor file access.
Other vulnerabilities in knowns
See all- CVE-2026-86544High
Vulnerability in knowns versions before 0.30.0 contain an authorization bypass vulnerability where mutating code actions are incorrectly classified as read-only operations. Attackers with read-restricted sessions can exploit code.replace to modify permission configurations and escalate privileges on subsequent calls.
- CVE-2026-86541High
Vulnerability in knowns versions before 0.30.0 contain a path traversal vulnerability in the handleCodeReplace() function that allows attackers to overwrite arbitrary files outside the project root. Attackers can supply absolute paths or relative paths containing directory traversal sequences to write malicious content to sensitive files like shell startup scripts or SSH configuration files.
- CVE-2026-86540High
Vulnerability in knowns versions before 0.30.0 fail to validate the settings.lsp.languages binary field in project configuration files, allowing attackers to execute arbitrary binaries by crafting a malicious .knowns/config.json file. When a repository with a crafted configuration is opened, the unvalidated binary path is executed twice under the user's account without any verification.
- CVE-2026-86539High
Vulnerability in knowns through 0.33.0 contains a server-side request forgery vulnerability in the POST /api/embedding-models/test endpoint that issues outbound requests to caller-supplied destinations without validation. Attackers can enumerate internal hosts and cloud metadata endpoints by observing transport error messages that reveal network reachability information.
- CVE-2026-86538High
Vulnerability in knowns versions before 0.30.0 contain a path traversal vulnerability in the POST /api/templates/preview endpoint that allows unauthenticated attackers to read arbitrary files. Attackers can supply directory traversal sequences in the templateFile parameter to bypass path restrictions and read sensitive files like credentials and configuration through the JSON response.
- CVE-2026-86543Critical
Vulnerability in knowns before version 0.30.0 serves the management API without authentication on all network interfaces by default, with no password required on fresh installations. Attackers can access the unauthenticated /api/tunnel/start endpoint to provision a public tunnel and republish the API at a publicly accessible address.
- CVE-2026-86542Critical
Vulnerability in knowns before 0.30.0 fails to validate import names in the import routes, allowing unauthenticated attackers to write files outside the imports directory. Attackers can supply traversal sequences in the name parameter to escape the imports directory and overwrite arbitrary files writable by the server process.
Original NVD description (English source)
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.