🤖⚠️ NEW MCP FLAW — REMOTE ATTACKERS CAN ESCAPE THE INTENDED FILE BOUNDARY CVE-2026-81491 affects with-context-mcp through version 3.0.7. The flaw is remotely reachable, requires no authentication, and public exploit code is already available. CyberSignal Priority: 🟠 HIGH 📅 August 27, 2026 🆔 CVE-2026-81491 🏷️ MCP · Path Traversal · AI Security · File Access The vulnerability affects several MCP functions: ingest_notes teleport_notes sync_notes project_folder Improper path handling allows crafted input to traverse outside the directory the MCP server is supposed to access. Conceptually: attacker-controlled path ↓ insufficient path validation ↓ ../ traversal ↓ access outside allowed workspace The CVE record rates it 7.3 HIGH under CVSS 3.1. More importantly: • network reachable • no privileges required • no user interaction • public exploit reference exists The project was reportedly notified, but the CVE record says the maintainer had not responded at publication time. ⚠️ There is currently no evidence this is being actively exploited in widespread attacks. Public PoC ≠ active exploitation. 🛡️ Defender action If you run with-context-mcp: • inventory versions immediately • restrict network access • run the MCP process with minimal filesystem permissions • validate and canonicalize paths • monitor unexpected filesystem access The broader MCP security lesson keeps repeating: AN AI TOOL SHOULD NEVER INHERIT MORE FILESYSTEM ACCESS THAN IT ACTUALLY NEEDS. Sources: CVE · VulDB · NVD
Post summary
CVE-2026-81491 is a path‑traversal flaw in with‑context‑mcp with a publicly available PoC but no evidence of active exploitation, and the text offers mitigation steps and technical details.