CVE-2026-86541: high-severity vulnerability in knowns-dev knowns
knowns before 0.30.0 Path Traversal via code.replace MCP action
Published · Updated
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.2epss 0.8%
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:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N
Affected products
knowns-dev · knownsRelated CVEs — knowns-dev knowns
In the same product, most dangerous first.
CVE-2026-86439HIGHknowns before 0.30.0 Path Traversal via MCP doc and memory toolsEPSS 1.1%CVE-2026-86538HIGHknowns before 0.30.0 Path Traversal via templateFile parameterEPSS 1.0%CVE-2026-86543CRITICALknowns before 0.30.0 Unauthenticated Management API ExposureEPSS 0.9%CVE-2026-88899CRITICALknowns before 0.31.0 External Control of Agent Working Directory via x-opencode-directory HeaderEPSS 0.8%CVE-2026-86775HIGHknowns before 0.30.0 Path Traversal via Document APIEPSS 0.7%CVE-2026-86542HIGHknowns before 0.30.0 Path Traversal via Import NameEPSS 0.7%
References
https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/mcp/handlers/code.go#L588-L646https://github.com/knowns-dev/knowns/commit/a2c98fc5c313463576c9348beeec6a74ddd7333bhttps://github.com/knowns-dev/knowns/releases/tag/v0.30.0https://github.com/knowns-dev/knowns/security/advisories/GHSA-f539-xgc6-xw7qhttps://www.vulncheck.com/advisories/knowns-before-0.30.0-path-traversal-via-code-replace-mcp-action