CVE-2026-86541 Details
Description
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.
A path traversal vulnerability has been identified in Knowns versions prior to 0.30.0, specifically within the handleCodeReplace() function of the MCP 'code' tool. This vulnerability allows attackers to overwrite arbitrary files outside the project root by supplying absolute paths or relative paths with directory traversal sequences. Exploitation can target sensitive files such as shell startup scripts or SSH configuration files. The issue arises because the 'replace' action is not properly registered as a write operation in the permission registry, allowing it to be executed even in read-only environments.
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 10, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/mcp/handlers/code.go#L588-L646 | [email protected] | Source CodeVendor |
| https://github.com/knowns-dev/knowns/commit/a2c98fc5c313463576c9348beeec6a74ddd7333b | [email protected] | Source CodeVendor |
| https://github.com/knowns-dev/knowns/releases/tag/v0.30.0 | [email protected] | Release NotesVendor |
| https://github.com/knowns-dev/knowns/security/advisories/GHSA-f539-xgc6-xw7q | [email protected] | AdvisoryTechnical AnalysisVendor |
| https://www.vulncheck.com/advisories/knowns-before-0.30.0-path-traversal-via-code-replace-mcp-action | [email protected] | AdvisoryBundleRemedy |
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-dev knowns | <= 0.29.1 (semver) |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 10, 2026 | CVE Modified | CISA-ADP |
| Sep 7, 2026 | New CVE Received | [email protected] |