A swap accepts a caller-supplied token path without validating endpoints, letting an attacker route through malicious or worthless pools, or end in the wrong token.
require(path[0]==tokenIn && path[path.length-1]==tokenOut, "bad path"); router.swapExactTokensForTokens(amt, minOut, path, to, dl);
The SaferICO scanner runs 201 detectors over your Solidity source, SAFE-0086 among them. Paste an address or the source itself — a small per-scan fee, shown before you sign, or unlimited on any plan.