Algorithm confusion in JWT verification

Code reviewSecuritySenior–Staff~28 min

Review this Node.js JWT verification middleware.

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Separate real bugs from style. Rank issues by severity, point at the root cause rather than the symptom, and suggest a concrete fix, specific and kind.

0:00 of about 28 min

Mark a line and say what kind of problem it is.0 findings

1const jwt = require('jsonwebtoken');

3function authenticate(req, res, next) {

4 const token = req.headers.authorization?.split(' ')[1];

5 const header = JSON.parse(Buffer.from(token.split('.')[0], 'base64').toString());

6 const decoded = jwt.verify(token, SECRET, { algorithms: [header.alg] });

7 req.user = decoded;

8 next();

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