mcp-ssh-tool has file transfer path policy bypass and bearer token comparison hardening
Date: 2026-05
Affected: npm/mcp-ssh-tool
Attack vector: path-traversal
Category: vulnerability-disclosure
Severity: High
CWE: CWE-208
CWE-22

## Summary `mcp-ssh-tool` has released version `2.1.1` with security hardening for transfer path authorization and HTTP bearer authentication. The release addresses: - insufficient local path policy enforcement in transfer-related filesystem handling - incomplete canonicalization and segment-boundary handling for deny-prefix path policy checks - non-constant-time HTTP bearer token comparison ## Impact Affected versions may allow policy bypass in transfer path handling under specific configurations, and may expose a timing side channel in bearer-token comparison for HTTP deployments. ## Patched Version Upgrade to `mcp-ssh-tool >= 2.1.1`. ```bash npm install -g mcp-ssh-tool@latest ``` ## Workarounds For deployments that cannot immediately upgrade: - avoid exposing HTTP transport beyond loopback - use strict filesystem policy configuration - avoid granting MCP clients access to sensitive local transfer paths - monitor audit logs for unexpected transfer operations ## Credits Reported by `dodge1218`.


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