High severity · published Sep 7, 2026
CVE-2026-86541
knowns before 0.30.0 Path Traversal via code.replace MCP action
8.3
CVSS
0.8%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.8% · higher than 55% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KN
knowns · knowns-dev
before 0.30.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-86541
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-86541
github.com
https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/mcp/handlers/code.go#L588-L646
github.com
https://github.com/knowns-dev/knowns/commit/a2c98fc5c313463576c9348beeec6a74ddd7333b
github.com
https://github.com/knowns-dev/knowns/releases/tag/v0.30.0
github.com
https://github.com/knowns-dev/knowns/security/advisories/GHSA-f539-xgc6-xw7q
www.vulncheck.com
https://www.vulncheck.com/advisories/knowns-before-0.30.0-path-traversal-via-code-replace-mcp-action
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