CVE-2026-55609

Impact An arbitrary file write vulnerability (CWE-73, External Control of File Name or Path) exists in the consciousness-explorer component of sublinear-time-solver. The MCP export_state (and import_state) tool accepted a user-supplied filepath argument and passed it directly to fs.writeFileSync / fs.readFileSync without constraining the destination or rejecting path traversal. An attacker able to invoke the MCP tool could write or overwrite any file accessible to the server process (e.g. ~/.ssh/authorized_keys, application files), leading to integrity loss and potential service disruption. The same sink class was present in the main solver MCP server (saveVectorToFile / loadVectorFromFile). Affected versions - consciousness-explorer < 1.1.2 - sublinear-time-solver < 1.6.0 - sublinear (crates.io) < 0.2.0 Patches - consciousness-explorer@1.1.2 - sublinear-time-solver@1.6.0 - sublinear@0.2.0 State/vector files are now confined to a dedicated directory (overridable via $CONSCIOUSNESS_EXPLORER_STATE_DIR / $SUBLINEAR_SOLVER_VECTOR_DIR), a basename-only contract is enforced (rejecting separators, .., NUL/control chars, hidden files, and Windows reserved names), and files are opened with O_NOFOLLOW | O_CLOEXEC mode 0o600. Covered by 14 regression tests in tests/consciousness/safe-path.test.mjs. Breaking change: callers must now pass a basename, not an absolute path. Workarounds Do not expose the MCP server to untrusted clients; restrict export_state to trusted local users; run the server under a low-privilege account with a restricted working directory.

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