Code RoomOpen redirect via backslash bypass

HardPrep Room Coding #2068

Open redirect via backslash bypass

Code reviewCode quality & reviewSenior–Staff~22 min

Review this Node post-login redirect that already rejects `//` and absolute URLs.

What a strong answer looks like

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 22 min

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

1app.get('/login/callback', async (req, res) => {

2 const user = await exchangeCode(req.query.code);

3 if (!user) return res.redirect('/login?error=1');

4 req.session.userId = user.id;

5

6 const next = req.query.next || '/';

7 if (!next.startsWith('/') || next.startsWith('//')) {

8 return res.redirect('/');

9 }

10 res.redirect(next);

11});

Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.